LEILA FADEL, HOST:
Police officers say rape cases can be tough to solve. There are seldom witnesses or cameras. And a survivor's memory can be spotty. That's because of the way trauma affects the brain's ability to record and retrieve details. Reporter Sammy Caiola at CapRadio in Sacramento says knowing this could help police crack more cases. But more importantly, it can reduce further harm to victims and help them heal. And a warning to our listeners that this story discusses sexual violence.
SAMMY CAIOLA, BYLINE: Annie Walker says she woke up one morning in 2019 with only a fuzzy recollection of the previous evening.
ANNIE WALKER: There was, like, this huge bruise all over my arm. And I had bruises all over my body. And - but my - I literally had no idea, like, what had happened.
CAIOLA: She says over the next few days, details and images of that night in Sacramento started to come back. She'd been at a bar and restaurant. She remembered being left alone with the perpetrator and trying to push him away. One week later, Walker reported an assault to the sheriff's department. Then over the following days, more vivid memories popped up. He bent her over, pulled her pants down and penetrated her from behind. And he had a weapon.
WALKER: And I knew that there was a gun at my neck, at my back. Like, it was just clear.
CAIOLA: Neuroscientists and psychologists say it's common for trauma survivors to have gaps in their recall of a violent event, and for some details to return to them weeks and months later. It's related to the way their brains lay down memory during an assault. But if police officers don't know that, they may assume a survivor is making something up. And experts say officers make that assumption more often with sexual assaults than other crimes. Harvard University psychologist Jim Hopper provides testimony in rape cases. And he says rape survivors undergo high levels of stress similar to what someone might experience in combat.
JIM HOPPER: We would never question the credibility of a soldier based on whether they can remember the exact sequence of those mortars coming in and which one, you know, blew off their friend's leg versus, you know, blew off that guy's arm. Would we expect them to remember everything in great detail? No.
CAIOLA: He says when confronted with a threat, the brain's defense circuitry takes over. That shifts it into survival mode, which causes someone to fight, flee or freeze. Annie Walker says the night she was raped, that's exactly how she reacted.
WALKER: I felt, like, paralyzed. Like, I couldn't even, like, feel, like, my limbs.
CAIOLA: In moments of severe stress, Hopper says the brain might only take in information that's critical to survival. For example, a rape victim might remember a hand grabbing their neck but forget what the attacker was wearing. And unfortunately, what someone remembers and what a detective needs to build a case don't always line up. Walker says the Sacramento detective she worked with put a lot of pressure on her to produce details right away.
WALKER: I remember I just kept saying, I don't know. I don't know. I don't know. Or, I mean, I think I might have said, like, I don't know, blue jeans, maybe. Like, I just felt like - I almost felt like I had to, like, say something.
CAIOLA: And Walker says they gave her a hard time when she remembered the gun more than a week after the attack.
WALKER: Yeah. I feel like I was just extremely, like, cross-examined on the phone. Like, why didn't you remember a gun? That's, like, a really important thing. And, like, I couldn't explain why I couldn't remember things that had happened or why they were coming back to me the way that they did.
CAIOLA: Criminal justice scholars say police officers need to be more aware of how trauma affects the brain and be patient with survivors. And in some departments, officers are learning to use the science in how they approach rape cases. Detective Nicole Monroe is with the Elk Grove Police Department in a suburb of Sacramento.
NICOLE MONROE: I will always tell the people that I interview, hey - especially if it's fresh - you're going to remember things for who knows how long. Bits and pieces will come back. Smells will come back. Sights will come back. When you think of these things, give me a call and let me know.
CAIOLA: Police may also be able to draw more details out of survivors if they change the way they ask questions. Carrie Hull used to be a police detective who investigated rapes. Now she's a consultant and teaches law enforcement officers how to be prepared for the memory gaps involved in trauma.
CARRIE HULL: We really view it as important and as needing of expertise as, like, your SWAT team.
CAIOLA: She says officers who can avoid leading questions and allow survivors to provide the information they do know might do better at bringing rapists to justice. There isn't research yet proving that's true. But multiple experts say this is a best practice that can reduce the harm that can happen when survivors report and aren't interviewed skillfully. For Annie Walker, she says it would have made a huge difference if an officer had told her it was OK to not remember everything right away and that survivors need that assurance.
WALKER: They need to feel like the way that things are happening in their mind is, like, normal for them, I guess, you know?
CAIOLA: Walker's case was never forwarded to the district attorney's office. It's been more than two years since the assaults. And she's still trying to heal from the rape and how police treated her.
For NPR News, I'm Sammy Caiola in Sacramento.
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FADEL: This story comes from NPR's partnership with CapRadio and Kaiser Health News.
(SOUNDBITE OF GOLDMUND'S "THREAD") Transcript provided by NPR, Copyright NPR.
