That has been the practice in Philadelphia for a few years, said Kathleen M. Brown, an associate professor of nursing at the University of Pennsylvania, who worked with the city police on revising their approach. When a rape exam is done, she said, a victim decides whether to give the evidence to the police and talk with an officer; if she does, the police explain the next steps and assure her that she can stop cooperating at any time, but they do not ask her if they should continue to investigate.

“Agreeing to report is not the same thing as saying, ‘I’ll get up on the stand and testify,’ and that conversation shouldn’t happen until much later, if it happens at all,” Dr. Brown said. Historically, many officers disbelieved the accusers or wanted to avoid hard-to-prove cases, and discouraged women from reporting rapes, she said, “so we’ve worked hard to get to this point.”

It is unknown how many Florida State University students report sexual assaults to the police. Most occur off campus and are reported to the Tallahassee Police Department, which does not tally which accusers are students, nor does the state attorney’s office. Sixteen on-campus rapes were reported to the Florida State University police from 2011 through 2013, but those include nonstudent victims and exclude sex crimes other than rape.

But records from Refuge House, a Tallahassee nonprofit group, obtained as part of an examination of the Winston case, show that in those three years, its nurses were called to hospitals to examine and counsel 63 Florida State students seeking treatment for sexual assault. Of those, 55 reported the assault to the police.

Interviews with prosecutors and a review of local news reports turned up just two arrests in that span by the Tallahassee police for sexual assaults on Florida State students. University police records show no arrests for forcible sex offenses from 2007 through 2013. Unlike burglary, sex is often consensual, so proving rape is hard; in some cases, prosecutors agreed with the police that the evidence did not support charging the suspect.

It is widely accepted that if a victim is adamant that she does not want a case pursued, law enforcement should take that into account. But reports from both city and university police departments show that unless accusers say firmly that they want cases investigated and prosecuted, officers have called them uncooperative and called off investigations.