1. Introduction to the Model
The Strategic Use of Evidence (SUE) Model is a structured interviewing approach designed to enhance deception detection by controlling when and how evidence is disclosed during an interview. Rather than revealing all evidence upfront, investigators withhold and strategically introduce information to test the subject’s account.
The purpose of this model is to identify inconsistencies, contradictions, and deceptive behavior by comparing the subject’s statements against known evidence. It relies on the principle that truthful individuals are more likely to provide consistent accounts, while deceptive individuals may unknowingly contradict available evidence.
For trainees, this model is essential because it teaches strategic thinking, timing, and control of information, which are critical skills in investigative interviewing. It also reinforces the importance of planning and evidence management.
The SUE Model is widely used in modern investigations because it improves the accuracy of deception detection without relying on coercion or pressure.
Ultimately, the model emphasizes that when evidence is revealed can be as important as the evidence itself.
2. Background of the Model
The Strategic Use of Evidence Model was developed by psychologists Pär Anders Granhag and Leif A. Strömwall in Sweden. Their work was grounded in research on cognitive psychology, deception, and investigative interviewing.
They observed that traditional interviewing practices often involved revealing evidence too early, which allowed suspects to adapt their stories to fit the known facts. This reduced the investigator’s ability to detect deception.
To address this issue, they developed a model based on the idea that withholding evidence creates cognitive challenges for deceptive individuals. When suspects are unaware of what the investigator knows, they are more likely to:
- Provide incomplete or inaccurate accounts
- Commit to statements that later contradict evidence
The model is supported by research showing that liars experience higher cognitive load, making it difficult for them to maintain consistency.
The SUE Model has since been widely adopted in law enforcement, intelligence, and security interviews, particularly in Europe and other regions emphasizing ethical, evidence-based interviewing practices.
It remains highly relevant due to its ability to improve interview effectiveness without coercion.
3. What is the Model
The Strategic Use of Evidence Model is an evidence-based interviewing technique that involves withholding and gradually revealing evidence to test the consistency of a subject’s account and detect deception.
It aims to expose contradictions and inconsistencies through controlled and strategic questioning.
4. Components / Stages of the Model
The SUE Model follows a structured process that integrates planning, controlled disclosure, and analytical comparison of statements.
- Evidence Review and Planning
The investigator begins by conducting a detailed review of all available evidence, including:
- Physical and forensic evidence
- Witness statements
- Digital records and timelines
The investigator identifies:
- Key evidence points
- Information that can be strategically withheld
- Areas where contradictions are likely to occur
A questioning plan is developed to determine:
- When to ask specific questions
- When to disclose evidence
- How to sequence topics
Key Principle: Effective use of evidence requires careful planning and timing.
- Free Account and Initial Statement
The interview begins by asking the subject to provide a full, uninterrupted account of events.
At this stage:
- No evidence is revealed
- The subject speaks freely
- The investigator observes content and behavior
This allows the investigator to capture the subject’s uncontaminated version of events, which becomes the baseline for comparison.
Key Principle: Early disclosure of evidence reduces the ability to detect inconsistencies.
- Strategic Questioning Without Disclosure
The investigator asks specific and detailed questions related to the evidence without revealing what is known.
Examples:
- Asking about time, location, or actions
- Probing areas where evidence exists
The goal is to:
- Test the subject’s account
- Encourage them to commit to specific details
Deceptive individuals may provide answers that conflict with known evidence, while truthful individuals are more likely to remain consistent.
Key Principle: Commitment to a version of events creates opportunities for contradiction.
- Gradual Disclosure of Evidence
Once the subject has been committed to their account, the investigator begins to introduce evidence strategically.
This may involve:
- Revealing contradictions step-by-step
- Presenting evidence after the subject has provided a statement
- Using evidence to challenge inconsistencies
The timing of disclosure is critical. Evidence is revealed only when it can:
- Maximize impact
- Expose contradictions clearly
Key Principle: Evidence should be revealed strategically, not immediately.
- Confrontation of Inconsistencies
The investigator highlights discrepancies between the subject’s statements and the evidence.
This involves:
- Comparing statements with known facts
- Asking the subject to explain contradictions
- Observing reactions to evidence
Deceptive individuals may:
- Change their story
- Provide weak explanations
- Show signs of stress or confusion
Truthful individuals are more likely to:
- Maintain consistency
- Provide logical explanations
Key Principle: Contradictions are powerful indicators of deception or incomplete disclosure.
- Evaluation of Responses and Credibility
The investigator evaluates the subject’s responses based on:
- Consistency with evidence
- Ability to explain discrepancies
- Behavioral reactions
This stage helps determine:
- Credibility of the subject
- Need for further investigation
- Next investigative steps
Key Principle: Credibility is assessed through evidence-based comparison, not assumptions.
Overall Integration of the Components
The stages of the SUE Model work together to create a controlled and strategic interview process:
- Planning identifies opportunities
- Free account captures baseline
- Questioning creates commitment
- Disclosure exposes contradictions
- Evaluation supports decision-making
Critical Insight: The model’s strength lies in information control, allowing investigators to reveal evidence at the most effective moment.
5. How the Model Works in Investigation
In practice, the investigator begins with careful planning and evidence review, followed by obtaining a free narrative from the subject.
The investigator then asks targeted questions without revealing evidence, encouraging the subject to commit to specific details. Once the account is established, evidence is introduced strategically to test consistency.
Any contradictions are explored further, and the subject’s responses are evaluated against known facts.
This process allows investigators to identify deception, confirm truthfulness, and guide investigative decisions effectively.
6. Case Study / Practical Example
In a burglary investigation, the investigator has CCTV footage placing a suspect near the scene. During the interview, the suspect is asked to provide a full account, claiming they were elsewhere at the time.
The investigator asks detailed questions about the suspect’s whereabouts without mentioning the CCTV evidence. The suspect provides specific details, committing to their version of events.
At a later stage, the investigator reveals the CCTV footage, highlighting the contradiction. The suspect becomes inconsistent and struggles to explain their presence near the scene.
This leads to further questioning, eventually resulting in an admission.
This example demonstrates how the SUE Model uses strategic timing of evidence disclosure to expose deception.
7. Application of the Model (Where & When to Use)
The SUE Model is most effective in:
- Criminal investigations involving suspects
- Cases with strong supporting evidence
- Situations requiring deception detection
- Intelligence and security interviews
It is particularly useful when:
- Investigators need to test the credibility of a subject
- Evidence must be used strategically
It may be less effective when:
- Evidence is limited or weak
- Immediate disclosure is legally required
Key Principle: Use the model when evidence can be strategically controlled.
8. Strengths of the Model
The model offers several strengths:
- Enhances detection of deception
- Encourages truthful and detailed accounts
- Reduces reliance on coercive techniques
- Provides a structured and strategic approach
- Supported by scientific research
9. Limitations of the Model
The model also has limitations:
- Requires strong planning and preparation
- Less effective with limited evidence
- Skilled suspects may adapt under pressure
- Requires high level of interviewing skill
- Timing errors may reduce effectiveness
10. Summary of Key Points
The Strategic Use of Evidence Model is a powerful interviewing approach that focuses on withholding and strategically revealing evidence to detect deception.
By controlling the flow of information, investigators can expose inconsistencies and assess credibility more effectively. The model emphasizes planning, timing, and analytical comparison, making it highly effective in modern investigative practice.
For trainees, mastering this model develops strategic thinking, evidence management, and advanced interviewing skills, which are essential for successful investigations.