Eyewitness Identification Expert Testimony in Criminal Trials

Few forms of evidence can be more persuasive to a jury than an eyewitness who points to the defendant and says:

“That’s the person I saw commit the crime.”

But decades of scientific research have demonstrated that eyewitness memory is not a video recording. Memory can be affected by lighting, distance, stress, the presence of a weapon, the length of time the witness observed the suspect, suggestive identification procedures, post-event information, and numerous other factors.

The Illinois Supreme Court confronted these issues in People v. Lerma, 2016 IL 118496.

The court recognized the substantial body of scientific research concerning eyewitness identification and held that, under the circumstances of the case, the trial court abused its discretion when it excluded the defense’s expert testimony on the reliability of eyewitness identification.

The decision is particularly important because the prosecution’s case depended heavily on eyewitness identification.

Federal criminal defense attorney Michael J. Petro has more than 35 years of criminal defense experience representing individuals in serious criminal cases involving eyewitness identification, forensic evidence, expert witnesses, and challenges to unreliable government evidence.

Why Eyewitness Identification Can Be Unreliable

A witness can be completely sincere and still be wrong.

This distinction is fundamental.

Most eyewitness-identification cases do not involve a witness deliberately lying. Instead, the problem may arise from the way human perception and memory operate.

A witness first has to perceive an event.

The witness then has to store that information in memory.

Later, the witness must retrieve the memory when asked to identify a suspect or testify in court.

Problems can occur at every stage.

Poor viewing conditions can affect what was originally perceived. Passage of time can affect what is remembered. Information learned after the event can influence later recollection.

The witness may nevertheless become increasingly confident in the identification.

That is one reason eyewitness-identification evidence deserves careful scrutiny.

People v. Lerma

In People v. Lerma, the Illinois Supreme Court considered whether a criminal defendant should have been permitted to present expert testimony concerning the reliability of eyewitness identification.

The defendant was charged with murder.

The prosecution’s case depended substantially on eyewitness identifications.

The defense sought to call Dr. Geoffrey Loftus, a psychologist with expertise concerning human perception and memory.

Dr. Loftus proposed to explain scientific principles that could help the jury evaluate the reliability of the identifications.

The trial court excluded the testimony.

The Illinois Supreme Court concluded that, under the circumstances presented, excluding the expert was an abuse of discretion.

The court reversed and remanded for a new trial.

Why Lerma Was an Important Decision

For many years, courts were skeptical about allowing experts to testify concerning eyewitness reliability.

One common assumption was that jurors already understood the weaknesses of eyewitness testimony through ordinary life experience.

Another was that cross-examination and closing argument were sufficient to expose unreliable identifications.

Scientific research challenged those assumptions.

The Illinois Supreme Court recognized in Lerma that significant developments in the scientific understanding of memory and identification had occurred.

Some factors affecting eyewitness reliability are intuitive.

Others are not.

And some commonly held beliefs about eyewitnesses may actually be incorrect.

That is where expert testimony can become important.

An Eyewitness Can Be Confident and Wrong

One of the most important concepts in eyewitness-identification cases concerns confidence.

Jurors may naturally assume that a witness who is extremely confident must be accurate.

But confidence and accuracy are not interchangeable.

A witness’s confidence can be affected by events occurring after the original observation.

For example, feedback indicating that the witness selected the “correct” suspect can strengthen the witness’s confidence without improving the accuracy of the original memory.

By the time the witness testifies at trial, the witness may be completely certain.

The relevant question remains:

How reliable was the identification process that produced that certainty?

Poor Lighting Can Affect Identification

Lighting is an obvious but important consideration.

A witness who observes someone in bright daylight may have a substantially different opportunity for identification than a witness observing a person:

• At night;
• Under a streetlight;
• Inside a dark vehicle;
• Through tinted glass;
• From inside a building;
• In shadows; or
• Under rapidly changing lighting conditions.

The fact that the witness could see a person does not necessarily establish that the witness could perceive enough facial detail to make a reliable identification later.

The defense should examine the actual viewing conditions rather than relying upon general testimony that the witness “got a good look.”

Distance Matters

Distance can substantially affect the ability to perceive facial detail.

A witness may accurately describe:

• Clothing;
• Height;
• Approximate build;
• Movement; or
• General appearance

while having insufficient visual information to reliably identify the person’s face.

Defense counsel should determine precisely where the witness was positioned and where the suspect was located.

Photographs, measurements, diagrams, surveillance video, and scene inspections can sometimes be important in evaluating the claimed identification.

Duration of Observation Matters

A witness may describe an event as lasting a long time when the opportunity to observe the suspect’s face was actually very brief.

The relevant issue is not necessarily how long the entire incident lasted.

The question may be:

For how long did the witness actually have an unobstructed opportunity to observe the person’s face?

Seconds matter.

A witness may have been looking at a weapon, attempting to escape, talking to someone else, or focusing on another part of the event.

The defense should reconstruct the observation period as precisely as possible.

Stress Can Affect Perception and Memory

Crimes frequently occur under stressful conditions.

A witness may be frightened, surprised, threatened, injured, or attempting to protect another person.

It might seem intuitive that an extremely stressful event would produce a permanently accurate memory.

The relationship between stress and memory is more complicated.

High levels of stress can impair aspects of perception and later identification.

Expert testimony can help jurors understand why an emotionally powerful memory is not necessarily an accurate identification.

The Weapon-Focus Effect

When a weapon is present, a witness’s attention may be drawn toward the weapon rather than the perpetrator’s face.

This phenomenon is commonly described as the weapon-focus effect.

The presence of a firearm can be particularly significant.

A witness confronted with a gun may naturally focus attention on:

• The gun itself;
• Where it is pointed;
• Whether it is being fired;
• How to escape; or
• How to survive the encounter.

That allocation of attention can reduce the amount of facial information encoded into memory.

An eyewitness expert can explain this phenomenon to the jury.

Cross-Racial Identification

Research has also examined identification accuracy when the witness and the person being identified are of different races.

This issue is commonly referred to as the cross-race effect or own-race bias.

The point is not that a cross-racial identification is automatically unreliable.

It is a factor that may affect identification accuracy and may not be fully understood by jurors without expert explanation.

Whether the issue is relevant depends upon the facts of the particular case.

Disguises and Facial Obstructions Matter

A witness’s opportunity to identify someone can also be affected by partial disguises or obstructions.

Examples include:

• Hats;
• Hooded clothing;
• Masks;
• Sunglasses;
• Facial coverings;
• Facial hair;
• Hair covering part of the face; or
• Objects obstructing the witness’s view.

The defense should determine exactly which facial characteristics were visible during the observation.

A witness who saw only part of someone’s face may later unconsciously fill gaps in the original memory with information obtained after the event.

Memory Is Not a Video Recording

One of the most important principles an identification expert can explain is that human memory does not operate like a surveillance camera.

People do not simply record an event and later replay an unchanged copy.

Memory is reconstructive.

What a person remembers later can be affected by information received after the original event.

This characteristic of memory has major implications for eyewitness identification.

Post-Event Information Can Affect Memory

After witnessing a crime, a person may receive additional information from:

• Police officers;
• Other witnesses;
• News reports;
• Social media;
• Photographs;
• Family members;
• Prosecutors; or
• Repeated questioning.

That later information can become intertwined with the witness’s original memory.

The witness may no longer be able to distinguish clearly between:

what was actually observed during the crime

and

what was learned afterward.

This does not require dishonesty.

It is a feature of human memory.

Suggestive Identification Procedures Can Affect Reliability

The procedures police use to obtain an identification can also matter.

Potential identification procedures include:

• Photo arrays;
• Live lineups;
• Showups;
• Single photographs;
• Surveillance photographs;
• Social-media photographs; and
• In-court identifications.

The defense should examine how the procedure was administered.

Questions may include:

• Did the officer administering the lineup know who the suspect was?
• Was the witness told that the suspect might not be present?
• Did one photograph stand out?
• Did police say anything before the identification?
• Did police provide feedback afterward?
• Was the witness exposed to the suspect’s photograph previously?
• Did witnesses communicate with each other?
• Was the suspect presented alone?

The procedure can affect both the initial identification and the witness’s later confidence.

Showup Identifications Require Particular Scrutiny

A showup typically occurs when police present a single suspect to a witness rather than presenting a lineup or photo array containing several people.

The procedure is inherently suggestive because the witness knows police have detained the person being shown.

That does not automatically make every showup identification inadmissible.

But the circumstances should be carefully examined.

The defense should determine what police told the witness, how much time passed after the crime, where the showup occurred, what the suspect looked like, and whether the witness had already received information about the person police detained.

Repeated Exposure to the Same Suspect Can Matter

A witness may encounter the same suspect repeatedly during an investigation.

For example, the witness may:

1. See the perpetrator during the crime.
2. View a photograph later.
3. See the suspect at a preliminary hearing.
4. See media coverage.
5. Meet with prosecutors.
6. Identify the defendant again at trial.

By trial, the defendant’s face may be extremely familiar.

But familiarity with the defendant at trial does not necessarily establish that the witness accurately perceived the perpetrator during the original event.

An expert can help explain the distinction.

An In-Court Identification Can Be Extremely Powerful

An eyewitness pointing across the courtroom at the defendant can create a dramatic moment.

But the jury should understand the history leading to that identification.

By the time of trial, the witness may have seen the defendant repeatedly.

The defendant is also sitting in an obvious location—at counsel table beside the defense attorney.

The defense should therefore examine the original identification evidence rather than treating the courtroom identification as an independent confirmation.

Acquaintance Identifications Are Different

Not every identification case involves a stranger.

A witness may claim to recognize someone already known to the witness.

That can substantially change the analysis.

If the witness has known the defendant for years and had a clear opportunity to recognize the defendant, many concerns associated with stranger identification may carry less weight.

But acquaintance does not automatically eliminate every reliability issue.

The defense may still examine:

• Lighting;
• Distance;
• Duration;
• Disguise;
• Stress;
• Whether the witness actually saw the person’s face;
• Prior disputes;
• The witness’s initial description; and
• When the witness first named the defendant.

The significance of each factor depends upon the facts.

Initial Descriptions Can Be Critical Evidence

One of the most valuable pieces of evidence in an identification case may be the witness’s first description of the perpetrator.

Defense counsel should obtain the earliest available record of:

• Race;
• Sex;
• Approximate age;
• Height;
• Weight;
• Hair;
• Facial hair;
• Clothing;
• Tattoos;
• Scars;
• Voice;
• Vehicle; and
• Other distinguishing characteristics.

The initial description should then be compared with the defendant’s actual appearance at the time of the offense.

Significant differences can be important.

What Did the Witness Say Before Police Had a Suspect?

Timing matters.

A description given before police identify a suspect may provide particularly useful evidence of what the witness actually remembered.

Once police present a suspect or photograph, later descriptions can potentially be influenced by that exposure.

The defense should therefore create a chronology of every identification-related event.

Police Reports May Not Tell the Entire Story

Police reports often summarize an identification in a few sentences.

For example:

“The witness positively identified the defendant.”

That statement may conceal important information.

How long did the witness take?

What instructions were given?

Did the witness hesitate?

What words did the witness actually use?

Did the witness say:

“That’s him.”

or:

“I think that’s probably the person.”

Those statements are not equivalent.

Whenever possible, the defense should obtain the original recording, photographs, lineup documentation, notes, and other evidence concerning the procedure.

Witness Certainty Should Be Documented Immediately

A witness’s confidence should ideally be documented at the time of the initial identification and before the witness receives confirming feedback.

That contemporaneous confidence statement may be more informative than the witness’s confidence months or years later at trial.

A witness who initially says:

“I’m about 60 percent sure.”

may later testify:

“I have absolutely no doubt.”

The development of that confidence can become an important subject for cross-examination and expert testimony.

Cross-Examination Alone May Not Be Enough

Cross-examination remains one of the principal tools for challenging eyewitness testimony.

Defense counsel can expose:

• Poor lighting;
• Short viewing time;
• Inconsistent descriptions;
• Delayed identification;
• Suggestive procedures; and
• Changes in confidence.

But Lerma recognized an important point.

Some scientific principles concerning perception and memory are not necessarily within the ordinary knowledge of jurors.

Cross-examination can establish the facts.

An expert can explain why those facts matter scientifically.

Those are different functions.

What Can an Eyewitness Identification Expert Explain?

Depending upon the facts and the court’s evidentiary rulings, an eyewitness expert may address subjects such as:

• Memory formation;
• Memory decay;
• Stress;
• Weapon focus;
• Exposure duration;
• Lighting;
• Distance;
• Cross-racial identification;
• Post-event information;
• Suggestive procedures;
• Confidence inflation;
• Repeated exposure; and
• The relationship between confidence and accuracy.

The expert generally does not tell the jury:

“This witness is wrong.”

Instead, the expert provides scientific information that helps jurors evaluate the identification evidence themselves.

The Expert Does Not Replace the Jury

This distinction is important.

The jury remains responsible for deciding whether an eyewitness is credible and whether the identification is reliable.

An expert’s role is to provide specialized knowledge concerning factors affecting perception and memory.

The expert can explain scientific principles.

The jury applies those principles to the evidence presented at trial.

Expert Testimony Must Satisfy the Rules of Evidence

An eyewitness expert is still an expert witness.

The proposed testimony must satisfy the applicable rules governing expert testimony.

In federal court, that generally means Federal Rule of Evidence 702.

The court considers matters such as whether the witness is qualified, whether specialized knowledge will help the jury, whether the testimony rests on a sufficient factual basis, and whether reliable principles and methods have been reliably applied.

State evidentiary standards vary.

Lerma involved Illinois law, but the broader issues concerning eyewitness reliability arise in both state and federal criminal cases.

A Motion in Limine May Be Necessary

Defense counsel seeking to present an eyewitness expert should address admissibility before trial.

A written motion can explain:

• The expert’s qualifications;
• The scientific principles involved;
• The particular identification problems presented by the case;
• Why the testimony will assist the jury;
• The limits of the proposed opinions; and
• The governing evidentiary authorities.

The motion should connect the expert’s proposed testimony to the specific facts of the case rather than simply presenting a general discussion about the fallibility of eyewitnesses.

The Expert Should Be Retained Early

Eyewitness-identification issues should be investigated early in the case.

An expert may need time to review:

• Police reports;
• Body-camera video;
• Identification procedures;
• Photo arrays;
• Lineup photographs;
• Witness statements;
• Transcripts;
• Surveillance video;
• Scene photographs;
• Lighting information; and
• Measurements.

Early consultation can also help defense counsel identify issues that might otherwise be overlooked.

Dr. Geoffrey Loftus and Eyewitness Identification

Dr. Geoffrey Loftus is a recognized expert in human perception, memory, and eyewitness identification.

His work has addressed how viewing conditions and psychological factors can affect a person’s ability to perceive and later identify another individual.

His proposed testimony was central to the Illinois Supreme Court’s analysis in Lerma.

But the importance of eyewitness expertise is not merely theoretical.

It can have a direct practical impact in a criminal trial.

Attorney Petro’s Use of Eyewitness Expert Testimony

In a subsequent criminal case, Attorney Michael J. Petro retained Dr. Geoffrey Loftus to evaluate eyewitness identification evidence involving two Chicago police officers.

The defense challenged the reliability of the identification by examining factors that included:

• Low lighting;
• Limited observation time;
• Divided attention;
• Possible weapon focus;
• Cross-racial identification; and
• Suggestive post-event information.

Dr. Loftus testified for the defense at trial regarding factors affecting the reliability of the officers’ identifications.

The defendant was found not guilty on all counts.

That case demonstrates the practical importance of examining eyewitness evidence scientifically rather than assuming that a confident identification must be correct.

Police Officers Are Eyewitnesses Too

An important lesson from eyewitness science is that police officers are not exempt from the limitations of human perception and memory.

An officer may be highly trained and completely sincere.

But the officer still perceives an event through the same human cognitive processes as any other witness.

Relevant factors can include:

• Darkness;
• Distance;
• Stress;
• Divided attention;
• Weapon focus;
• Short observation time; and
• Information learned after the event.

A badge does not transform human memory into a recording device.

Police identification testimony should be evaluated according to the actual circumstances under which the observation occurred.

Surveillance Video Can Change the Analysis

Modern criminal cases increasingly involve surveillance video.

Video can sometimes confirm an eyewitness identification.

But it can also demonstrate how difficult the original identification would have been.

Defense counsel should examine:

• Resolution;
• Frame rate;
• Camera angle;
• Lighting;
• Compression;
• Distance;
• Motion blur;
• Facial visibility; and
• Whether the video has been enhanced.

The question is not merely whether a person appears in the video.

The question may be whether the available visual information is sufficient to reliably identify that person.

Eyewitness Identification Can Be the Entire Case

Some criminal prosecutions contain:

• DNA evidence;
• Fingerprints;
• Video;
• Confessions;
• Digital evidence; or
• Physical evidence connecting the defendant to the crime.

Others do not.

Sometimes the prosecution depends almost entirely upon:

“That’s the person I saw.”

When identification is the central evidence connecting the defendant to the offense, the reliability of that identification deserves particularly careful examination.

That was one of the circumstances making the expert testimony in Lerma so significant.

Mistaken Identification Can Produce Wrongful Convictions

The consequences of eyewitness error can be enormous.

A mistaken witness may be sincere.

The police may sincerely believe the witness.

The prosecutor may sincerely believe the identification.

The jury may find the witness convincing.

And the identification can still be wrong.

That is why safeguards surrounding eyewitness evidence matter.

The criminal justice system must distinguish between confidence and reliability.

What Should Defense Counsel Investigate?

When identification is disputed, defense counsel should consider obtaining and reviewing:

• Every witness statement;
• The earliest description of the suspect;
• Photo arrays;
• Lineup records;
• Showup documentation;
• Body-camera recordings;
• Dashcam recordings;
• Surveillance video;
• Police photographs;
• Dispatch recordings;
• Officer notes;
• Communications among witnesses;
• Social-media exposure;
• News reports viewed by the witness;
• Prosecutor interview notes where discoverable; and
• Prior testimony.

A detailed timeline of the identification process can reveal information that is invisible when each event is considered separately.

The Lesson From People v. Lerma

People v. Lerma represents an important recognition that eyewitness identification involves scientific principles that may fall outside ordinary juror knowledge.

The decision does not mean eyewitness testimony is inherently unreliable.

Nor does it mean an identification expert must be permitted in every case.

The important principle is more measured:

When eyewitness identification is central to the prosecution and scientifically recognized factors affecting reliability are genuinely at issue, expert testimony may provide information that assists the jury in evaluating the evidence.

The jury can then decide what weight the identification deserves.

Experienced Criminal Defense Attorney for Eyewitness Identification Cases

Michael J. Petro has more than 35 years of criminal defense experience representing individuals in serious state and federal criminal cases.

Eyewitness-identification cases require more than asking whether the witness seems believable.

The defense should examine how the identification was formed.

That means investigating the original viewing conditions, the witness’s first description, the identification procedure, later exposure to the suspect, changes in confidence, and scientifically recognized factors affecting perception and memory.

When appropriate, an experienced eyewitness-identification expert can provide the jury with information necessary to evaluate that evidence accurately.

If you are facing criminal charges in which eyewitness identification is an important part of the prosecution’s case, contact criminal defense attorney Michael J. Petro to discuss the identification evidence and available defense strategies.