Incarceration Reporting Initiative
Shot in the head and just out of a five-month coma, 20-year-old Mario Carr, a young Black man, could barely nod his head when Long Beach police first interviewed him. Even so, he would go on to become LA County prosecutors’ star witness. Investigators would come to rely almost exclusively on his testimony, even as they failed to follow up on other leads and evidence. A patchwork of limited evidence and conflicting eyewitness statements should have flagged reasonable doubt in prosecutors’ minds. Yet together, the flimsy evidence would be crucial in “winning” the attempted murder case against the defendant, Erica Johnson, a Black woman. This three-part series examines the case, the science of brain injuries, and the apparent cognitive biases that led to Johnson’s conviction and life sentence.
Read the first part of the series here.
The attempt on Mario Carr’s life had been just one of nearly 3,000 violent crimes to occur in Long Beach in 2011, marking an increase from the previous year’s total of 2,735. How this trend affected police decision-making or priorities that year remains unclear.
Both physical and digital evidence in Carr’s case was limited. Police recovered a bullet casing but no gun; no call logs, text messages, or threatening social media posts; and limited eyewitness testimony. Carr himself was unable to speak, according to police report updates from January and February 2012.
Characterized as a “hit shooting” by one officer assigned to the LBPD gang unit, the case had stalled. Although homicide detectives Don Goodman and Scott Lasch had identified two persons of interest in the case, they could not technically call either one a suspect.
The first person, Carr’s neighbor Matt Clanton, had not been interviewed. The second person, Carr’s acquaintance Erica Johnson — who lived in an apartment building adjacent to the crime scene — had been interviewed but provided no probable cause for arrest.
By March, since Carr had survived the shooting and was expected to regain consciousness, Goodman and Lasch handed their case over to gang detectives Patrick Lyon and Bobby Anguiano. Goodman would later testify that he advised Lyon to “keep an open mind” regarding Johnson and Clanton.
Carr’s brain injuries were extensive. The bullet entered his skull just below his left ear and fragmented.. These fragments traveled at a slightly upward angle through Carr’s left cerebellum and occipital lobe, reaching into his right temporal region.
What structures within these regions were damaged remains unclear from medical reports and expert testimony. For example, the temporal lobe houses the hippocampus and the amygdala, two key structures within the limbic system, which is responsible for emotion, motivation, behavior regulation, and memory. Memory formation is also part of the function of the occipital lobe, which is responsible for visual as well as spatial processing.
Further complicating the trauma to these regions was Carr’s medical history. Records reviewed by Dr. Arthur Kowell, a neurologist and expert for Johnson’s defense, indicated that Carr had been diagnosed with attention deficit hyperactivity disorder (ADHD) as a child and later on, bipolar disorder. He’d dropped out of high school in 10th grade, had an unknown work history, and was “reportedly living in various arrangements.”
Kowell noted that upon admission to the hospital for the gunshot wound, Carr tested positive for lorazepam, morphine, and THC. In addition to the cannabis and opiates, Carr’s mother told doctors her son also used methamphetamine and alcohol, while Johnson had told police that ecstasy — a synthetic drug similar in structure to methamphetamine — played a role in her social interactions with Mario.
How the trauma and medical treatment affected Carr’s already disordered brain, then, is impossible to tell. Generally, as stated in a 2003 law review article, “Experts may not opine on credibility [because] [c]redibility is an issue for the jury.” This is why both Hoover and Kowell focused their expertise on the gunshot trauma and its effects during the trial.
According to Kowell’s review, Dr. Serina Hoover, Carr’s neuropsychologist at Rancho Los Amigos National Rehabilitation Center, evaluated Carr on Friday, June 8.
Carr’s ability to understand others’ questions and statements, Kowell wrote, “appeared intact and he was able to reliably respond to yes/no questions.” However, the responses could be unclear, requiring repetition.
Carr’s ability to communicate was additionally “negatively affected by reduce [sic] frustration tolerance possibly related to depressed mood and feelings of hopelessness.” During Hoover’s evaluation, Carr had rated his feelings a 10 — the most intense — on a scale of 1 to 10.
Further, Carr could only participate in interviews lasting up to 40 minutes. “As time passed the patient would become agitated and began to pull at his shirt, a gesture which he used to express frustration and/or fatigue,” Kowell stated.
To Hoover, this emotional expression reflected awareness of his own situation and deficits, she would later testify, indicating higher-level cognitive abilities.
However, in 2017, Hoover’s evaluative practices would be called into question. When assessing NFL retirees seeking compensation from a landmark concussion settlement, the neuropsychological evaluations Hoover conducted failed to meet the standard of care required for approval of a monetary award in a civil case. A Special Master found that her “assessments often violated standardized procedures,” some of her test interpretations were incorrect, and she had “disregarded indicators of suboptimal effort.” The Special Master concluded that claims relying on her evaluation, testing, or opinions were to be denied.
What Carr’s TBI Meant for His Police Interviews
Whether or not detectives Lyon and Anguiano were aware of Hoover’s assessment of Carr, as well as whether they consulted with her prior to their own interviews, is unclear. Carr’s mother, Lashone Haywood, had reached out to Lyon in early June to tell him that Carr could answer “yes” and “no” questions with head movements. Lyon’s report of this call does not record whether Haywood told him anything else.
Carr’s physician confirmed that Carr would be able to participate in an interview, and that Carr had given his consent to do so. Because this first interview took place on Tuesday, June 12 — four days after Hoover’s initial evaluation — the detectives would have encountered two constraints: Carr’s limitations in expressive language, and his tolerance for lengthy interactions.
The kinds of yes / no questions Lyon was limited to asking may have seemed low-impact for a TBI patient. However, Jerrod Brown, a professor, trainer, researcher, and consultant who has extensively presented and published on traumatic brain injuries’ impact on criminal justice system outcomes, said that individuals affected by TBI, schizophrenia, or other conditions affecting brain function could tend to overrepresent their “yes” responses.
Alternatively, their nonverbal cues or tics, such as head nods, can communicate “yes” — or simply that the interviewee understands what the interviewer is saying. During an interview Lyon and Anguiano conducted in August, for example, it’s unclear at several points whether Carr clearly understood what he was being asked or how to respond.
Brown, the TBI expert, said another problem with yes / no questioning could be related to damage to the limbic system, the prefrontal cortex, and/or other brain structures. This kind of damage could result in challenges with emotional processing, in particular fear responses. “Maybe the person is overly compliant and they just want to people-please someone in a position of power or someone in a uniform,” he explained.
Physical factors can be in play, too. For one, Carr was likely in pain during that first interview with Lyon. During Hoover’s June 8 evaluation, Kowell wrote, Carr had “endorsed pain in his lower extremities which he… rated at 10/10” in intensity on a scale of 1 to 10.
Brown also referred to emerging evidence that the type and severity of a brain injury could impact the vagus nerve, which extends from the brain stem to the gut. That stress, in turn, could throw off the gut and dysregulate blood sugar.
Such medical issues can also affect memory. Similarly, medication side effects, along with sleep disturbances frequently associated with TBI, can affect cognitive functions. Daytime fatigue, Brown added, can affect the brain’s executive functioning, its “boss,” which guides decision making, problem solving, and reasoning.
“All of these things are so interconnected, so then the whole body’s not working properly,” Brown explained. “And then during an interview, a person might have more anxiety, more depression, more irritability.”
All of this, he added, could impact motivation. Indeed, towards the end of an hour-long session, Hoover later testified, Carr’s responses “would maybe start being inaccurate” owing to his suppressed frustration tolerance.
The Science of Brain Disorders’ Impact on Memory
Lack of awareness about these complexities has profound legal implications. For example, Brown noted that many TBI patients may be functioning at a younger level than their chronological age suggests. “You have to really be careful with the complexity of the question you’re asking, the vocabulary you’re using,” he explained.
The standard interviewing techniques typically taught to police do not suffice, even though they differ from interrogation tactics. While designed to be part of the investigative fact-finding process, these techniques are meant to be non-accusatory and non-persuasive.
Forensic interview techniques evolved to mitigate challenges that children and vulnerable adults can experience in standard interview settings. These interviews rely on open-ended rather than leading questions, developmentally appropriate language, a slow pace, and the avoidance of sensory or memory overload. Interviewers are trained to refrain from prodding or suggesting responses, which would be coercive of a vulnerable subject. People with speech, intellectual or cognitive challenges, including traumatic brain injuries, can still be forensically interviewed, but the protocols are different.
Brown said these techniques help interviewers to minimize the effects of impairments in brain function, striking a balance between a simple approach and the type of fact checking needed to ensure the patient understands, in their own words, what they just confirmed.
By the time they interviewed Carr in the summer of 2012, neither Lyon nor Anguiano had been trained in these techniques.
Public records from the California Commission on Peace Officer Standards and Training (POST) and the LBPD reflect that both detectives had received a total of four hours of refresher training in tactical and interpersonal communications in 2009 and 2011, respectively.
At the time, the courses focused mainly on trainees’ “ability to generate voluntary compliance through the art of persuasion.”
A POST records spokesperson said that as of 2020, the two courses had been incorporated into “strategic communications,” which does cover disabled people.
However, POST only introduced mental illness training in 2015, when it began to offer a non-mandatory crisis intervention course to comply with a new state law.
A Shaky Underpinning for a Criminal Case
Forensic interview training might have prepared Lyon and Anguiano to navigate several key challenges associated with relying on Mario Carr as a witness to his own attempted murder.
First: Carr’s general medical state, including inpatient treatments and therapies,. Although Lyon and Anguiano kept their interviews short — reportedly lasting just 15 minutes on June 12, and only nine minutes on August 30 — Lyon’s reports don’t indicate whether he was aware of other factors that might have affected Carr’s participation. For example, Carr’s sleep quality the night before, any kind of therapy that might have tired him, or any medical setbacks he’d experienced in the hours before the interviews could have affected his frustration tolerance.
The second issue was the dilemma of outside influences. In the August video recording, social chatter is audible in the background, contrasting with forensic interview protocols that call for minimal “disorienting and disconcerting” distractions.
More problematic, though, was the influence of Lashone Haywood and Jessica Carr. The week before Lyon and Anguiano’s interview, Haywood told Lyon she had asked her son questions about who had shot him.
The possibility that Haywood’s questioning might have contaminated Carr’s memory — long a known risk in law enforcement interviews, to the extent that both research and practical training material goes into detail on how to avoid it — does not appear to have been a consideration for the detectives.
Otherwise, Lyon might have taken extra care to document the case he was building. For instance, he and Anguiano might have opted to video record that first interview in June instead of merely capturing audio. (This recording was not introduced as a trial exhibit, and the only record available is the account Lyon detailed in his police report.)
Lyon also deviated from standard practice by presenting Carr solely with the photo of Johnson, the suspect.. By 2012, the focus of photo lineup research wasn’t how many photos to show, but on shifting from simultaneous to sequential showings.
A POST training document revised in 2008 focuses on a “photographic spread,” without recommending it be simultaneous or sequential. What the document does recommend is the use of at least six photographs. “Fewer than five photographs may make the selection impermissibly suggestive,” the document states — a violation of a suspect’s due process rights.
Kowell’s report did not address whether Carr had the cognitive capacity to look at a full “six pack” photo lineup of suspects, although Hoover’s trial testimony indicated that he “was able to identify he was at Rancho Los Amigos when given multiple choice options.” It’s also unclear how far Lyon held the photo from Carr’s face, or what Carr’s visual acuity was at the time.
After positively identifying Johnson, Lyon’s and Anguiano’s following questions in both the June and August interviews focused on the gun used to shoot Carr, specifically inquiring about the shooter’s proximity — whether it was closer than 50, 30, 20, 10, five feet, or within arm’s length.
Although Carr answered affirmatively each time, he stopped nodding his head. It is impossible to tell whether he could differentiate between numbers and the ranges they represented. Although Hoover testified later that the damage to Carr’s right temporal lobe had most likely affected his visual and spatial skills rather than memory, Kowell’s report refuted this claim.
Furthermore, research published in 2016 indicates that the left hippocampus plays a critical role in episodic verbal memory, while the right hippocampus — located in Carr’s injured temporal region — is believed to function more in spatial memory processing — the judgment of distance.
“[The] reliability of the patient’s memory relative to events which occurred on 12/27/2011 should be considered questionable and probably unreliable,” Kowell wrote. “It is medically probable that he instantaneously lost consciousness after the gunshot wound to the left occipital region, thereby making it medically improbable that he saw anyone who was standing behind him.”
Finally, Lyon sought to determine if Johnson had been alone in the alley. Yet, his line of questioning in August diverged in one key area.
In June, Lyon had seemed satisfied with Carr’s “no” response to his question about whether Johnson was alone in the alleyway. In August, however, he asked the question twice — immediately before and after questions about Carr’s relationship with Johnson.
Carr confirmed what Johnson had told homicide detectives when they interviewed her the previous December: the relationship was nonromantic, and Johnson was an acquaintance he’d known for three to six months.
The pivot in questioning may have confused Carr. At first, he told Lyon that Johnson was alone in the alleyway. Following the interview segment about his and Johson’s relationship, though, Carr contradicted his earlier statement. This time, he said she was with her “boyfriend.”
In the recording, Lyon’s voice pitches higher in surprise. He repeats the question a few different ways before asking whether the boyfriend, or Johnson, shot Carr.
Carr verbalized “Erica.” Lyon corrected himself to “keep it to yes or no questions” before completing the interview with a few additional questions about the boyfriend, including whether Carr knew him. Carr said he did not.
Carr’s conflicting responses following Lyon’s pivot raise an important question about suggestibility, a cousin of confabulation: the unintentional recollection of false memories.