Sample Scenario: The Confession

Agent MND was requested to interrogate and conduct a polygraph on a man suspected in the disappearance of a 16-year-old female, his step-daughter. No physical evidence had been discovered to tie the suspect to her disappearance. Investigating officers had little to go on in pursuit of their case. The suspect had never been placed under arrest - in fact, the suspect had volunteered for the polygraph. The day of the interrogation was Agent MND's second day on the case, which was already in its second week. He had had no previous contact with the suspect, and prior to meeting the suspect, his only involvement in the case had been an oral review of the Chief of Police's interviews with the suspect and his wife. Following a polygraph interview that lasted less than 10 minutes, the suspect had provided no information to initiate an arrest, yet stated that he wanted to leave for a while and would "call back later." Agent MND had a gut feeling that allowing the suspect to leave could lead to a volatile situation - he might harm himself or others. Moments later the suspect confessed to murdering the girl. A search of the suspect's automobile revealed a shotgun and shells, purchased the morning of the interrogation. The missing female's body turned up several weeks later near a river, following the recession of flood waters.

What He Knew

Agent MND had gleaned a number of pieces of information from the Chief's interviews with the suspect and the missing girl's mother (the Chief conducted the interviews because the department was small):

Suspect called himself a 'trucker,' and worked as stepvan operator.
Suspect's wife considered him 'domineering,' and noted that he hated her dog because it frequently urinated in their house and shed its coat.
Suspect had been married to his wife for six months, but separated for a couple of weeks.
Suspect was physically attracted to his daughter-in-law, but also thought she was lazy, spoiled, and promiscuous.
Suspect had attempted to control the daughter's behavior, but was not supported in this by his wife - this conflict had led to their separation.
Suspect had been at the home the day of the disappearance to mow the lawn.
Suspect's wife had warned him to not disturb the daughter while mowing, as she was sleeping.
Suspect originally claimed to have not entered the home, but later recalled having entered the garage to retrieve a tool.
Suspect had returned to the home the day after the girl's disappearance to clean carpets, as they were dirty from dog urine and hair.
Regional crime scene investigation team had revealed no physical evidence of struggle in the home.

The Interrogation

Agent MND had developed an interview plan. The suspect had been read his rights, but was not under arrest. As he attached the polygraph instrument to the suspect, Agent MND instructed the suspect that he would be 'running two charts' on the polygraph. He began the interview by asking the suspect questions about his character that gave the opportunity to choose truthful or false answers. A baseline of several of the answers was provided by the information gleaned from the interview with the suspect's wife. For example, Agent MND asked the suspect whether he'd ever harmed women in a relationship. The baseline answer, while not definitive, was that the suspect had been 'domineering.' The suspects verbal ('no') and nonverbal responses, as captured by the polygraph instrument, provided Agent MND a 'measurement' of the suspect's truthfulness. Agent MND asked other questions specific to his relationship with the missing girl, which he compared to his baseline measurement (i.e., answers inferred from the interview with his wife):

"What was your relationship with her?"
"Why would people think you are to blame for her disappearance?"
"Did you cause her disappearance?"
"Did you harm her?"

Agent MND describes his reason for selecting the strategy:

"This polygraph method is a balancing act. I present choices by my questions, choices about his character. I could use this tactic - called the Control Test - because I could identify a known lie - I had his wife's answers. If I didn't have a control, I might've conducted a 'Peak Attention,' where I build to questions toward the one I'm really after."

Agent MND's questions also attempted to provide the suspect with an opportunity to confess by seeking to blame the victim. Agent MND describes the strategy:

"People who are guilty will often show signs of RPM - Rationalization, Projection, and Minimalization. I'm trying to help him clear his mind to focus on the event. So I asked him about her in a way that opens him up to RPM. "She was bad, wasn't she?" "She pushed you, didn't she?" "She was a wild thing, wasn't she… always out late at night…"

After attaching the polygraph instrument, Agent MND began the interview. The first polygraph - which lasted '3 or 4 minutes' - demonstrated 'deception,' particularly on the key questions regarding the suspect's actions toward the missing girl. The deception confirmed Agent MND's suspicion - the suspect was involved in her disappearance. He conducted a second polygraph interview, using the same questions and order, to 'validate' the first chart.

Agent MND next removed the polygraph attachments, and moved the interview to interrogation - to attempt to gain a confession. Using the charts, Agent MND pointed out to the suspect the answers that demonstrated deception. The charts were left in plain view as Agent MND continued with questioning, repeating questions regarding the suspect's involvement in the girl's disappearance. The suspect now refused to answer, instead "tapping the charts and insisting, 'I'm sticking to my story." While his strategy at this point is often to attempt to evoke the RPM answers, Agent MND was surprised by the suspect's next utterance:

"He said, 'I'm going to leave now… I need to go talk to her mother…I need to find her, then I'll come back and tell you what I know.' He said this very early on, as I started to question him after the polygraph. I had a gut feeling about what he would do. If he left, he was going to find his wife and try to kill her. Other suspects have said this, and fled."

Agent MND believed he needed to get a confession at this point. He noted that he also needed to guard against a 'false confession.' He knew that suspects often want to 'relieve the pressure' that interrogation can put on them. According to Agent MND, some do this by trying to leave; others, particularly those with low IQ, and those under the influence or just coming off, can falsely confess as a means to end the high-pressure situation.

Agent MND was not permitted to detain the suspect. His strategy shifted with the urgency and the suspects responses:

"The suspect was still under suspicion, but we couldn't keep him. I started reasoning with him, and taking down the information he was giving. I was trying to delay, stall, stretch out to keep him there. I was looking for a confession. I asked him more questions:

Why do you want to talk to her?
Isn't she working?
What do you want to tell her?

He told me that he needed to tell her what happened. At that point, I told him not to tell me what happened, but suppose that he was going to tell her. I switched the interview to the third person… similar to 'what iffing,' or 'simon says,' or 'mother may I.' He began telling me what happened in the third person. I went over the scenario with him a couple of times, gradually asking him to tell me in the first person. When he finally did, I asked him to put it in writing. He again stated that he was 'sticking to his story.' I gave him a few seconds to reflect on his story…and when he realized he'd given me the truth, he said he would put it in writing."

Afterword

In addition to the shotgun and shells, as well as the body, turning up later, the crime scene was reevaluated to reveal blood stains, which had been partially removed by the suspect with the carpet cleaner.