During an investigation, detectives often develop an informal template that helps orient them to the case as quickly as possible.¹ For instance, a detective may intuitively classify an emerging case as a “sexual murder” because the victim is found naked and bound or a “domestic murder” due to a history of domestic assaults at the location. However, this does not mean that detectives are locked into this initial impression. With new evidence and fresh observation, the course of an investigation can and will change. 

Focusing too early on a specific investigative template can create problems down the road. This holds especially true because an initial template frames expectations and creates the foundation for further investigative inquiry, evidence collection, assessments of risk and who is pursued as a suspect.

A case study follows that focuses on a recent death investigation. It provides an example of how assumptions can influence an initial informal investigative template. The authors will briefly discuss initial circumstances, the scene and victimology. Next, assumptions that drove the initial investigative template will be assessed, followed by a general discussion of overcoming investigative assumptions and how these principles were applied to the current case.

Case Review

Initial Investigation

One Sunday night in late 2018, a local jurisdiction received a 911 call from a male subject, “Patrick,” requesting that an ambulance respond to his apartment. He stated that his girlfriend, “Gina,” had shot herself.² He also said she had a knife in her throat.  

When fire and police personnel arrived, they found Gina deceased and supine on the living room floor. Contrary to Patrick’s assertion in the 911 call, no sign of a gunshot wound existed, and officers did not find a gun. Gina, covered in blood, had an 8-inch serrated butcher knife protruding from the left side of her neck. Additionally, her right hand had been amputated and was found on the floor next to her. The medical examiner later would indicate that 1) the knife had transected Gina’s neck left to right at a downward angle, penetrating the top lobe of her right lung, and 2) her hand had been sawed off at the wrist from the posterior side.

After determining that there were no other occupants in the apartment, responding officers secured the scene. Within an hour, detectives arrived. They observed Gina's condition and found numerous bloodstains and pools of blood throughout the living room and kitchen. As a result, the detectives secured a search warrant for the apartment pursuant to a murder investigation. A door-to-door canvass of residents in the building revealed that 1) there had been an incident in the stairway of the apartment building 2 months prior in which Patrick had accused Gina of cheating, and 2) a resident heard an argument in the apartment earlier in the day.

In his initial statement to police and in subsequent interviews, Patrick said he left the apartment in the early afternoon and met up with friends. He admitted that he and Gina had a verbal argument because she wanted to go with him. However, Patrick did not want her to because he wanted to have time for himself. When he returned in the evening, Patrick found Gina on the floor, covered in blood with the knife in her neck. Patrick said he thought Gina had shot herself because there was a lot of blood in the apartment. He also stated his belief that Gina stabbed herself in the neck to make it look like he killed her. Patrick insisted that he did not kill Gina.

Further, Patrick said that he had been dating Gina for less than a year. He recalled two domestic incidents with her within the prior month, one of which resulted in his arrest. However, Gina later dropped the charge. According to Patrick, Gina usually did not leave the apartment and never had friends over. He indicated that she was raised by her mother and her mother's boyfriend and had spent a lot of time on the streets. Patrick also indicated that several months prior to her death, Gina had gone to Florida to meet with several former associates. Although he said she had been acting “weird” lately, Patrick said Gina did not speak about harming herself.

Patrick described Gina as an alcoholic. He said that she had recently fallen at various locations throughout the apartment following a long night of drinking at a local bar. Additionally, he said that in a separate incident, Gina fell and hit the kitchen counter when she had a seizure after taking homeopathic herb kratom. Patrick used both incidents to explain bruises found on Gina’s body. Further, Patrick said that Gina was a former heroin user and recently had been using prescription drugs, including some that she was stealing from him. On the day before her death, Gina ran out of gas several miles from their apartment and called Patrick for help. When he arrived to assist her, she appeared to him to be paranoid about returning to and entering the apartment.

Detectives also interviewed two of Patrick’s male friends. They confirmed he had been with them on the day of Gina’s death. During the interviews, one of the friends disclosed that he had a homosexual relationship with Patrick about 2 years prior. Both friends confirmed that Patrick and Gina had a volatile relationship. Patrick had revealed to them that Gina did not approve of his friendships and frequently teased him about his previous homosexual activities. They also indicated that Patrick thought Gina was trying to set him up for “something bad” and that he was trying to get her to move out, but she would not. 

A history of domestic issues and the level of violence at the scene seemed to point to “domestic murder.” The alibi offered by Patrick’s friends was not particularly compelling. Given that they viewed Patrick as a victim of Gina’s erratic behavior, one or both friends could be an accomplice. Patrick’s insistence that she committed suicide made no sense. Detectives felt it was only a matter of time before Patrick would confess to killing Gina.

Investigative Assumptions

The ability to make quick decisions during a fluid and emerging situation is important. However, it is also important to realize that early decisions are based on early assumptions made in the absence of complete information. Often, information in an investigation either changes or, when combined with new information, justifies a shift in investigative action. For this reason, while a quick decision based on initial assumptions may be necessary, the ability to revise such decisions in view of new information is essential.

Several factors, including, but not limited to, descriptions of the incident by dispatch and the responding officers, prior incidents at the same location and previous law enforcement contacts with those involved, can prime assumptions. Additionally, a detective’s professional, personal, social and cultural experiences create a lens through which initial observations are focused into assumptions. These factors can create an “anchoring bias,” resulting in a powerful predisposition toward an initial assumption or investigative template.³  

In the case study, the initial investigative template employed by detectives framed the circumstances as a “domestic murder.” Generally, a “domestic murder” implies several expectations and predispositions. It is expected that there will be a history of domestic violence between the offender and victim. In addition, an examination of the domestic relationship will reveal significant flash points, or topics that tend to heighten emotional content of arguments. Due to this emotional content, there may be significant violence or evidence of irrational behavior. Further, because of culpability, the domestic partner may be evasive and attempt to provide weak exculpatory information or excuses.

Anchoring becomes a significant problem when there is dogmatic adherence to supporting these initial assumptions. When this happens, a detective can become focused on explaining successive observations solely within the context of that anchoring bias. This creates “confirmation bias,” or the tendency to pursue information that only supports the initial theory to the exclusion or dismissal of contra-indicators.⁴ The danger of confirmation bias is that it creates a chain of reasoning not sufficiently tested or challenged; this can have deleterious effects on the integrity of a case.⁵ 

Initial assumptions frame initial expectations. These expectations are overlaid onto the emerging investigation to determine whether new information should be accepted, rejected or reinterpreted. For instance, detectives have experience-based expectations of what a murder “looks like” just as they have expectations of what a suicide “looks like.” In the case study, Patrick claimed that Gina committed suicide; however, this seems unlikely. It does not resemble any suicide that detectives have seen before. Additionally, in a “domestic murder,” the domestic partner is expected to lie and deflect. So, it is no surprise that when Patrick says he thinks Gina killed herself, it is seen as a weak attempt to mislead detectives.

One of the best ways to overcome confirmation bias stemming from initial assumptions is to challenge whatever initial template may be in use. Asking the question “What would change the nature of this case?” is the first step toward breaking down those assumptions. For instance, there are two main assumptions inherent to the initial “domestic murder” template. The first is that it is a murder, and the second is that the circumstances stemmed from a domestic relationship. To overcome the potential for confirmation bias in the case example, detectives focused on challenging both assumptions.

Overcoming Initial Investigative Assumptions

Initially, this case was framed as a murder. However, to overcome potential confirmation bias, detectives challenged this assumption and asked, “Could Gina have amputated her own hand and stabbed herself in the neck?” 

To amputate her own hand and stab herself in the neck, Gina would need to cut through multiple layers of tissue, bone and large nerves, resulting in excruciating pain. Objectively, nothing precluded Gina from physically inflicting these wounds on herself. She had full use of her left hand, and the angle of transection in her neck could be consistent with stabbing herself. However, from a psychological, emotional and pain-management perspective, it would have been unlikely for Gina to inflict these wounds on herself unless other factors affected her state of mind.

Yet, if it is possible that the injuries were self-inflicted, then this broadens the scope of the case to that of an equivocal death. Under these circumstances, it would be appropriate to create parallel investigative tracks, one that frames circumstances as a murder and one as a suicide. In a murder investigative track, there ought to be evidence that someone else had the opportunity, ability and motive to inflict the wounds on Gina. In a suicide track, evidence should exist that Gina had the opportunity, ability and motivation to inflict the wounds on herself. 

Opportunity

During the execution of the search warrant, detectives observed bloody footprints throughout the apartment. All of them belonged to Gina, and her bloody socks remained on her feet. The footprints covered all paths approaching and moving away from the body. Detectives also noted numerous trails of 90-degree blood drops next to the foot impressions left by Gina. All blood at the scene was tested and matched her. These observations were consistent with the idea that although she was bleeding profusely from her wounds (most likely the amputation), Gina was mobile and wandering around the apartment.

While it seems likely that Gina inflicted the wounds on herself, it is important to determine what might have motivated this behavior. To this end, detectives used a psychological autopsy to determine Gina’s risk for extreme self-harm.⁸ The purpose of a psychological autopsy is to examine behaviors and address the motivation or driving forces behind that behavior, not to provide a diagnosis.

It appears doubtful that anyone would be able to inflict these wounds on themselves if they were fully alert and oriented. Therefore, detectives explored the possibility that Gina was psychologically or emotionally disconnected from reality. An important consideration in a psychological autopsy is to avoid getting locked into preconceived notions of what a suicide should look like. Two key features to focus on in this case are 1) Gina’s potential for underlying psychological and emotional issues and 2) her potential for experiencing an altered mental state. These are not mutually exclusive, and both factors may have played a role in her death. 

An altered mental state is a variation in brain function that can influence an individual’s behavior.  It usually stems from a medical condition, mental illness or an ingested substance. Consequently, an individual’s past medical or mental history may hold the key to identifying clues about odd behaviors. Additionally, environmental factors, lack of sleep or stressful events can trigger an altered mental state. Sometimes, an altered mental state can meet the criteria of psychosis or an excited delirium. It is worth noting, when it comes to the rare event of self-amputation (or auto-amputation) of an upper extremity, like an arm or hand, the limited research available on the subject suggests that there is frequently an accompanying psychosis.⁹

Interviews with Patrick revealed that Gina had experienced auditory hallucinations and paranoia over the past 3 months or longer. These incidents included claims that people were watching her through air vents and late-night episodes in which she was found talking to unseen people. Further examination of her recent trip to Florida also revealed that Gina was temporarily committed to a psychiatric unit due to bizarre behavior and paranoid claims that people were trying to kill her. All these behaviors are indicators that she may have been suffering from delusions. Further, although Patrick insisted that Gina never said she wished to harm herself, she did respond to his accusations of infidelity by repeatedly banging her head against a wall.

Gina’s toxicology report was positive for alcohol and hydroxyzine (a central nervous system depressant), which is known to occasionally be mixed with cocaine. Further examination of her substance abuse history included heavy alcohol use occasionally mixed with marijuana. Both substances are associated with psychosis. In addition, her toxicology report was positive for an herbal remedy — mitragynine (kratom). Patrick indicated that she had begun taking kratom to control menstrual pain. However, Gina’s past medical history is significant for seizures that were noted directly following her ingestion of kratom. 

Ultimately, Gina’s psychological autopsy not only provides evidence she was exhibiting bizarre behavior that may indicate underlying illness or psychological issues but also shows she was a potential risk for substance-induced psychosis or excited delirium. It will probably never be known if Gina’s drug use contributed to the development of underlying mental illness or if her drug use was an attempt to self-medicate an undiagnosed mental illness. However, it does appear likely that she had a potential for self-harm as a result of these complex factors.

Conclusion

Initially, detectives working Gina’s death investigation did not consider suicide as a viable explanation. At first, only murder made sense. They had viewed the scene, though briefly, and formed a selective understanding of what had occurred — "domestic murder.” Detectives believed Patrick would eventually confess to killing Gina. They wrote a search warrant for the crime of murder. They did not believe the alibi Patrick’s friends offered and questioned the practicality of Gina cutting off her own hand and then stabbing herself in the neck. It did not seem logical. 

Detectives were not the only ones with initial doubts about suicide. Following the autopsy, the medical examiner classified Gina’s death as “undetermined, pending police investigation” because there was no definitive means to establish the wounds were self-inflicted based solely on the postmortem examination.¹⁹ Further, the medical examiner was not comfortable, at that point, that someone would cut off their own hand in the manner presented in this case.  

However, detectives recognized that in Gina’s death, disconfirming evidence was much more probative than confirmatory evidence. Suicide is usually determined through the exclusion of other possibilities — for example, proving that only the victim was present. While it is difficult to find a rational explanation for Gina’s behavior, detectives determined that she was the only one who had the opportunity to cut off her own hand and was most probably experiencing an altered mental state. These investigative findings significantly reduced the probability of homicide, and the medical examiner made a final determination that the manner of Gina’s death was suicide. 

With every investigation, there are always risks of getting it wrong. Consequently, there are several practical reasons to administratively treat an initial death investigation as a murder — for instance, writing and executing search warrants to seize and preserve relevant evidence and conducting thorough interviews of possible involved persons. This ensures that perishable information is not lost, even if the nature of the investigation changes (e.g., from suspected suicide to suspected homicide). Additionally, if the need arises to use evidence in prosecution, strict procedural adherence will ensure the smooth admission of that evidence in the proceedings. 

Even with practical reasons to treat a death investigation as a murder, it is important not to allow the assertion of “murder” to create anchoring and confirmation biases that reinforce initial investigative assumptions. This means that while preservation and documentation of evidence is paramount, that same evidence should be continuously assessed and reassessed in light of new information.

Constructive scrutiny of investigations remains a critical and humbling necessity in finding the most probable explanation of what occurred. In this pursuit, law enforcement decision makers should never be reluctant to ask, “What would change the nature of this case?”