A complex criminal investigation is rarely solved by asking one perfect question.
Investigators may need to interview victims, witnesses, suspects, professionals, and people whose role in the case is still unclear.
Their accounts can conflict, memories may be incomplete, new evidence can appear halfway through an enquiry, and an apparently simple interview may suddenly create several new investigative leads.
This is where applying the PEACE Interview Model in complex criminal enquiries becomes particularly useful.
PEACE is an information-gathering framework built around five phases: Planning and Preparation, Engage and Explain, Account, Closure, and Evaluation. The approach is designed to help interviewers obtain full and accurate accounts rather than simply push someone toward a confession.
The College of Policing identifies PEACE as the framework used for investigative interviewing and emphasizes professionalism, rapport, structured questioning, active listening, and careful evaluation.
In complicated investigations, those principles matter even more. A well-conducted interview does more than produce answers – it can identify contradictions, generate new lines of enquiry, test evidence, and reveal what investigators still do not know.
What Is the PEACE Interview Model?
PEACE was developed as a structured approach to investigative interviewing, particularly within policing in England and Wales.
The five letters provide a simple way to remember the process:
P stands for Planning and Preparation.
E stands for Engage and Explain.
A covers Account, Clarification and Challenge.
C means Closure.
The final E means Evaluation.
Although that structure sounds straightforward, PEACE is more than a five-step checklist.
It represents a broader shift away from confession-driven interrogation toward information gathering.
The College of Policing describes the purpose of professional interviewing as obtaining a full and accurate account while maintaining fairness, integrity, and an open investigative mindset.
Suspect interviews can provide explanations, possible defences, alibis, and entirely new lines of enquiry – not simply admissions.
That distinction is important.
If the only objective is “get the suspect to confess,” an interviewer may start interpreting every response through an assumption of guilt.
If the objective is “obtain reliable information and test it against the evidence,” the investigation remains much more flexible.
Information Gathering Instead of Confession Hunting
International guidance has increasingly supported this information-gathering philosophy.
The United Nations Manual on Investigative Interviewing for Criminal Investigation describes rapport-based investigative interviewing as a methodical approach for obtaining accurate and reliable information while respecting the dignity and rights of interviewees.
The manual itself uses the PEACE framework as a step-by-step model.
The Méndez Principles on Effective Interviewing take a similar position, promoting science-based, rapport-oriented interviewing as an alternative to coercive interrogation.
This matters because the quality of an interview affects much more than the conversation in the room.
Poor information can send an entire investigation in the wrong direction.
Planning and Preparation: Where Complex Interviews Are Really Won
One of the easiest mistakes is assuming that interviewing skill begins when the recording starts.
Usually, it begins much earlier.
The College of Policing describes planning and preparation as one of the most important phases of effective interviewing.
Interviewers should review the investigation, identify available material, establish objectives, consider the interviewee’s characteristics, and decide how the interview will be structured.
In a simple enquiry, preparation may involve reviewing several statements and photographs.
A complex investigation can be very different.
The interviewer may have hundreds of pages of statements, forensic results, CCTV footage, phone records, financial data, timelines, previous accounts, and unresolved contradictions.
Trying to remember everything during the interveiw is unrealistic.
Build an Interview Strategy, Not Just a Question List
A strong interview plan should identify what investigators already know and, just as importantly, what remains uncertain.
Suppose investigators are examining an organized fraud involving five suspects, several companies, hundreds of transactions, and encrypted communications.
The interviewer might identify topics such as relationships between individuals, access to accounts, specific payments, ownership of devices, meetings, and explanations for unusual transactions.
But simply writing 70 questions is not necessarily good planning.
The interviewer needs to understand how the topics relate.
Which issues should be explored before evidence is disclosed?
Which answers can later be checked independently?
Which topics are central to proving or disproving involvement?
Which contradictions require clarification?
A structured topic map is often more useful than a rigid script.
Complex interviews are conversations with investigative objectives, not oral questionnaires.
Think About Evidence Before You Reveal It
Evidence disclosure also needs planning.
Imagine investigators possess CCTV showing a suspect at a particular location.
Immediately telling the suspect, “We have CCTV proving you were there,” may produce a response – but it also gives away exactly what investigators know.
An information-gathering approach may first explore the person’s own account.
Where were they?
Who were they with?
How certain are they?
How do they explain their movements?
Evidence can then be introduced at an appropriate point to test the account.
The objective is not to trick the interviewee.
It is to obtain an uncontaminated account before allowing disclosed information to shape it.
Engage and Explain: Rapport Is an Investigative Tool
Rapport sometimes gets misunderstood as being friendly to suspects.
That is too simplistic.
Professional rapport means creating conditions in which the interviewee understands the process and is able to communicate effectively.
The College of Policing emphasizes active listening, openness, professionalism, interest in the interviewee, and consideration of personal characteristics when establishing rapport.
This can be especially important when interviewing people who are frightened, defensive, traumatized, angry, confused, or suspicious of authorities.
Explain the Interview Clearly
Interviewees should understand why the interview is happening and what it will broadly cover.
A clear route map reduces uncertainty.
For example, an interviewer might explain that the discussion will cover the person’s relationship with another individual, their movements on a particular date, certain communications, and anything else relevant that emerges.
In a complex enquiry, this structure also helps the interviewer.
Without it, interviews can drift between unrelated issues until neither participant is completely sure what has been covered.
Rapport does not mean avoiding difficult questions.
A good interviewer can remain respectful while challenging serious inconsistencies.
In fact, a professional relationship may make those challenges more productive because the interviewer has established that the purpose is to understand the account rather than simply win an argument.
Research also supports the broader importance of rapport. A 2024 meta-analysis covering 60 studies found that rapport and relationship building, presentation of evidence, and cognitive facilitation were among the approaches associated with obtaining more valuable information.
Account: Let the Interviewee Give Their Version First
The Account phase is where much of the substantive information emerges.
One of its most important principles is surprisingly simple: give people enough opportunity to talk.
Interviewers often know far more about the case than the interviewee realizes. That creates a temptation to dominate the conversation.
A better starting point is usually an open invitation.
A witness might be encouraged to describe what happened in their own words.
A suspect may be invited to provide their account of the relevant event or allegation.
The interviewer listens carefully, identifies topics requiring further exploration, and avoids interrupting every time something interesting appears.
The College of Policing recommends free recall in witness interviewing and emphasizes allowing pauses, active listening, and prompts that encourage the person to continue without unnecessarily introducing new information.
Open Questions Produce More Than Rapid-Fire Closed Questions
Compare two approaches.
One interviewer asks: “Were you at the warehouse at 9 p.m.?”
Another says: “Tell me everything you remember about what you did after leaving the restaurant.”
The first question may produce one fact.
The second could generate information about travel, companions, locations, vehicles, phone calls, timing, and unexpected events.
Closed questions still have a role, especially when clarification is needed.
The problem comes when the entire interview becomes a long sequence of narrow questions that allows the interviewer to control the narrative.
Open questions let investigators discover things they did not know enough to ask about.
That is particularly valuable in complex criminal enquiries.
Clarifying Accounts Without Contaminating Them
A free narrative is only the beginning.
Once the person has provided an initial account, the interviewer can divide it into manageable topics and explore those areas more systematically.
This is where good questioning becomes critical.
The interviewer might ask for descriptions, sequences, locations, conversations, relationships, actions, or explanations.
Questions should be clear and generally deal with one issue at a time.
Multiple questions such as “Where did you go, who was there, what did you talk about, and did you see the blue car?” create obvious problems.
Which part is the answer responding to?
Leading questions can be even more problematic because they may introduce information into the account.
This is particularly important with children, vulnerable interviewees, or people who may be highly suggestible.
The College of Policing specifically identifies suggestibility as an issue interviewers need to consider and notes that some individuals require additional protections.
Separate What the Interviewee Knows From What Investigators Know
This becomes extremely useful later.
Suppose a witness independently mentions a damaged red suitcase that investigators deliberately never described publicly.
That detail may carry investigative significance because it apparently came from the witness’s memory rather than from the interviewer.
If the interviewer had previously asked, “Did you see the damaged red suitcase?”, that distinction would disappear.
Good interviewing preserves the evidential value of spontaneous details.
Challenge: Test the Account Without Turning the Interview Into a Fight
Challenge is one of the most misunderstood parts of PEACE.
It does not mean shouting, accusing, or repeatedly insisting that an interviewee is lying.
It means testing the account against relevant information.
Suppose a suspect says they did not communicate with Person B for six months.
Investigators have records showing repeated communications during that period.
A structured challenge allows the interviewer to establish the claim clearly, present the conflicting information appropriately, and invite an explanation.
The important part is the last step.
There may actually be an explanation investigators have not considered.
Perhaps the communication records involve a shared device.
Perhaps the suspect disputes ownership of the account.
Perhaps investigators misunderstood a piece of data.
Or perhaps the original statement cannot survive the evidence.
Either way, useful information has been produced.
Contradictions Are Investigative Opportunities
Complex cases are full of contradictions.
Witness A says the meeting happened on Tuesday.
Witness B says Wednesday.
Digital records suggest Thursday morning.
A poor investigation may simply choose the version that best fits its preferred theory.
A better one identifies the contradiction as something that needs resolving.
PEACE helps because the interviewer is encouraged to clarify and challenge rather than prematurely decide that one person is lying.
Memory errors, confusion, different perspectives, deliberate deception, and incorrect investigative assumptions can all produce inconsistent accounts.
The job is to distinguish between them as carefully as possible.
Why a Non-Coercive Approach Matters
The ethical argument against coercive interrogation is clear.
There is also a practical evidence-quality argument.
A 2024 systematic review examining 29 experimental studies across 27 research articles compared accusatorial, information-gathering, and direct-questioning approaches.
Information-gathering produced significantly more true confessions than direct questioning in the pooled analysis, while accusatorial conditions produced significantly more false confessions than information-gathering conditions.
Those studies were largely experimental and should not be interpreted as a perfect simulation of every real-world police interview.
But the overall pattern matters.
Pressure can generate answers.
That does not automatically mean those answers are reliable.
The aim of investigative interviewing should be accurate information, not merely apparent cooperation.
Confirmation Bias Can Enter the Interview Room
Another danger appears when the interviewer already feels certain about guilt.
Research has shown that investigator expectations can influence the tactics used during questioning and may contribute to processes associated with false confessions.
This is one reason planning should include alternative possibilities.
Before interviewing, investigators can ask themselves:
“What evidence would change our current theory?”
That question is incredibly useful.
If the answer is “nothing,” the investigation may no longer be genuinely testing its hypothesis.
Applying PEACE to Witnesses, Victims, and Suspects
The same broad framework can structure different types of interviews, but the interviewer’s objectives and legal responsibilities are not identical.
A witness interview may focus strongly on memory retrieval and uncontaminated free recall.
A victim interview may also require consideration of trauma, vulnerability, safety, communication needs, and appropriate support.
A suspect interview introduces additional legal safeguards and questions around evidence, potential defences, legal advice, cautioning, and disclosure.
In England and Wales, College of Policing guidance states that suspects are interviewed under PACE using the PEACE model, while witness interviews are also structured through PEACE.
The framework should never replace jurisdiction-specific law.
Investigators working elsewhere need to apply local requirements regarding legal representation, recording, detention, silence, vulnerable persons, interpreters, and admissibility.
Complex Enquiries May Require Specialist Interviewers
Not every interview should automatically be given to whoever happens to be available.
Major crime, terrorism, organized crime, child abuse, vulnerable witnesses, and investigations involving huge volumes of evidence may require additional expertise.
Multiple interviewers also need clearly defined roles.
The College of Policing warns that two interviewers asking questions in an unstructured manner is unlikely to achieve the interview’s objective.
One person might lead the discussion while another monitors evidence, notes emerging topics, or checks the interview plan.
Coordination matters.
Otherwise the interview can feel like two people competing to ask the next clever question.
Closure: Do Not Let a Good Interview End Badly
Closure is easy to underestimate.
After two or three hours of interviewing, everyone may simply want to finish.
But the closing stage can protect the quality of everything that came before it.
The interviewer should check whether important areas have been covered, allow the interviewee an opportunity to add or clarify information, and explain what happens next where appropriate.
A useful question can be surprisingly broad:
“Is there anything important about what we have discussed that I have not asked you about?”
Sometimes the answer is no.
Sometimes it creates an entirely new investigative lead.
The interviewer should also avoid ending in a hostile or dismissive way simply because difficult challenges occurred earlier.
Today’s suspect can become tomorrow’s important information source.
Today’s witness may need to be interviewed again after new evidence appears.
Professional closure protects the working relationship and the integrity of the process.
Evaluation: The PEACE Stage Investigators Often Forget
The final E stands for Evaluation.
It is arguably one of the most valuable parts of the model – and one of the easiest to rush.
The interview may be finished, but the investigation is not.
Interviewers need to evaluate both the information obtained and their own performance.
What new facts emerged?
What needs independent verification?
Which answers conflict with existing evidence?
Were new witnesses identified?
Does digital or forensic evidence need to be obtained?
Has the original hypothesis become stronger or weaker?
Could another interview now be necessary?
That is investigative evaluation.
There is also interviewer evalution.
Did the interviewer talk too much?
Were enough open questions used?
Was an important topic accidentally skipped?
Did frustration affect the interview?
Was evidence disclosed too early?
Could a better challenge have been made?
Professional interviewing develops through this kind of review.
The College of Policing treats interviewing as a skill requiring learning, practice, supervision, and maintenance rather than something officers automatically know how to do.
Using PEACE Across a Complex Investigation
The biggest benefit of PEACE may become visible when an enquiry contains dozens of interviews rather than one.
Imagine an investigation involving multiple suspects, 15 witnesses, CCTV footage, financial records, phone extractions, DNA evidence, and vehicle-location data.
Each interview creates information.
That information must feed back into the investigation.
Witness 4 identifies a previously unknown meeting.
Digital examination confirms communication between two participants.
Suspect 2 provides an explanation.
Financial records partially support that explanation but reveal another transaction.
Investigators then revise the plan for Suspect 3.
This is why the final E in PEACE connects naturally back to the first P.
Evaluation generates new planning.
The model is not really a straight line.
In complex enquiries, it becomes a cycle:
Plan → Interview → Evaluate → Investigate → Re-plan → Interview again if necessary.
That cycle helps prevent interviews from becoming isolated procedural tasks.
They become active parts of evidence development.
The Model Does Not Replace Investigator Judgment
PEACE is a framework, not a script.
A skilled practicioner still needs legal knowledge, listening ability, communication skills, evidence awareness, flexibility, and judgment.
Unexpected information may require the plan to change.
A vulnerable interviewee may need breaks.
A suspect may produce a detailed alibi requiring immediate investigation.
New evidence may fundamentally alter the enquiry.
Following PEACE effectively therefore does not mean mechanically completing five boxes.
It means using structure to support better thinking.
Applying the PEACE Interview Model in complex criminal enquiries helps investigators move away from confession-focused questioning and toward systematic information gathering.
Planning keeps interviews connected to investigative objectives. Rapport encourages communication. Open accounts provide information investigators may not have anticipated.
Clarification and evidence-based challenge test the reliability of those accounts, while closure and evaluation turn interview results into new investigative action.
The real strength of PEACE is that it treats an interview as part of a larger investigative process rather than a contest between interviewer and interviewee.
For investigators, students, and criminal justice professionals, the practical lesson is simple: do not judge a successful interview by how dramatic it feels. Judge it by whether it produces reliable information that can be checked, challenged, and used to move the enquiry forward.