TAMPA — Since 2007, only one of 19 rape cases involving students investigated by the University of South Florida police has faced prosecution.

That case resulted in 10 years of probation and no prison time for the assailant, who pleaded guilty to raping his roommate's friend.

This lack of prosecution in campus rape cases is a statewide phenomenon. Records collected from USF and eight other Florida universities found that prosecutions are nearly nonexistent. In 2012 and 2013, only two cases out of more than 50 reported have faced prosecution. Both of those cases involve the same suspect at Florida Gulf Coast University.

Victim advocates and some state attorneys say the rate of prosecution for campus rapes is lower than sexual battery cases that happen outside the collegiate setting.

"In general, yes, they're harder to prosecute," chief assistant state attorney for Tallahassee Georgia Cappleman said. "Her conduct and guilt, her lack of memory due to alcohol, all of these things contribute."

Local prosecutors say uncooperative victims often stymie their efforts. Others like Cappleman and USF victim's advocate Nanci Newton question whether investigators place too much responsibility on victims as a way to avoid pursuing difficult cases.

National leaders are calling upon universities to do more, both to promote awareness of the issue and protect victims. The White House, after circulating statistics estimating that one in five college women will be sexually assaulted, issued a series of recommendations this year. USF, which already had some of the steps in place, will distribute its first climate survey to students this spring as a result. But some people worry that a lack of law enforcement aggressiveness might be undercutting their efforts.

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Each year, the victim's advocacy office at USF counsels about 40 to 50 students who say they have been sexually assaulted, said Newton, the director of the USF Center for Victim Advocacy and Violence Prevention. Not all of these assaults happened on campus and therefore some fall outside the jurisdiction of USF police.

But of the 19 cases involving students reported to USF police from 2007-2013, only five made their way to the Hillsborough State Attorney's Office. In several instances, the investigation ended after prosecutors advised detectives the case would be difficult to prove in court. But in four of the cases filed by police, prosecutors still chose not to move forward.

In September 2010, a student reported a sexual battery to USF police after waking up after a party without her pants on and suspecting she had been raped.

The victim admitted she was drinking and smoking marijuana that night, but she knew the name of the person she suspected had assaulted her. Detectives interviewed the fellow student, who explained that he and the victim went to an apartment on campus after drinking and he kissed the woman and "proceeded to have sex." According to the report, police said the man had sex with the victim "while she remained asleep and physically unable to communicate her unwillingness."

The man wrote a letter during the interview detailing the events of the night.

"I did something and I believe I should confess to it," he wrote. "That's it."

The case was "direct filed" to the State Attorney's Office — a term used when charges are cited but the suspect is not arrested. But even with a confession, prosecutors decided not to pursue the case.

"Despite repeated attempts by the State, the victim has not contacted authorities to assist with the prosecution of this case," the letter of release said.

Rita Peters, head of the sex crimes division, said the law prevents prosecutors from accessing confessions before they can prove a crime occurred.

"In order to get into the confession, I have to prove I had a sexual battery," Peters said. "If I have a victim that won't cooperate or move forward, I can't prove that."

Both Peters and USF investigators frequently cited an uncooperative victim as a reason not to move forward with a case.

In 2013, a woman reported to USF police she was raped after attending a toga party and drinking "hunch punch" — a vodka fruit drink. She described how the suspect drove her home after the party and they made out on the bed. When he tried to escalate things, she told him no. The suspect then began to have sex with the woman and repeatedly told her to "just relax," the police report said.

However, the woman told detectives she did not want to prosecute or investigate the crime, but wanted to report its occurrence "in case another female comes forward involving (him) with similar circumstances."

In 2010, a student reported that a friend raped her in her dorm room after she invited him over for a study session.

She told police the 20-year-old man initiated sex without her consent, telling her "I'm stubborn" and "You know this is going to happen."

The man told detectives he "pushed farther than he should have," but said he "would have never forced sex if he knew she didn't want it," according to a police report.

Hillsborough prosecutor Carol Hooper reviewed the case and declined to file charges, saying there wasn't enough evidence.

Later that year, a freshman said she was raped after a party by two men who woke her up from a chair and walked her to her bedroom. The two men assaulted her while she continually said "No, stop it, no" and pushed them, according to the police report.

She reported the assault immediately. Police conducted several interviews with the woman, suspects and witnesses. They photographed the room and collected evidence including the suspects' DNA.

But prosecutors said proving the case beyond a reasonable doubt would be difficult. The victim, after filing the case and speaking repeatedly with detectives, decided not to pursue it.

"There is probable cause in this case," the letter of release said. "However, in order to file criminal charges the State must prove the facts of the case by a much higher standard of proof beyond a reasonable doubt. … The victim has requested this case not be prosecuted."

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Campus rape investigations often put a greater burden on the victim to make decisions early on regarding prosecution than other crimes, Cappleman said. This pressure, coupled with already low reporting numbers, is likely one of the factors leading to such low prosecution rates for campus rapes.

By comparison, in both 2012 and 2013, Hillsborough County Sheriff's Office and Tampa Police Department, the largest agencies in Hillsborough, made approximately 100 arrests on sexual battery charges. The county prosecuted 20 sexual battery cases in 2012 and another 26 in 2013, according to the Hillsborough County Clerk of Circuit Court.

"I don't think we need to put that ball in our victim's court immediately when she's still suffering from the trauma of the assault," Cappleman said. "A case can always be dismissed, but it can't always be investigated later.

"I would say that the ones that do report generally could be viewed as wanting to proceed," Cappleman said. "And while they may be nervous and hesitant to want to testify in a trial, which anyone would be, I find that they generally will hang with you as long as you hang with them."

But Newton, with USF's victim advocacy office, thinks the lack of prosecutions here goes beyond a hesitant victim.

"This prosecutor's office doesn't prosecute the non-stranger batteries," Newton said, referring to the Hillsborough State Attorney's Office. "And it is not for lack of trying on the part of our campus police, because they don't have a say in whether it's prosecuted or not."

Peters said the lack of prosecution isn't based on poor police investigations.

"There's not a single case I can think of where I would go back and say, 'I can't believe that detective did that or did not do that,' " Peters said.

Instead, the inability to prosecute rests on other factors, she said, such as limited memories, societal pressures, the unwillingness of the victim, and the often contradictory accounts of accuser and accused.

Newton agrees those barriers exist, but she said she also has worked with many willing, cooperative victims. However, she said, once prosecutors learned there was alcohol involved, they didn't want to proceed.

"Why aren't they willing to try?" Newton said. "If you started prosecuting those cases, eventually you're going to start getting some convictions. Athens, Ga. Madison, Wis. There's a lot of places that prosecute these cases with great success."

In August, a former University of Wisconsin football recruit was sentenced to a year in jail after he was convicted of raping a student in her dorm room.

In the one USF case that did face prosecution since 2007, the man walked away with 10 years probation. Samuel Cesaire was arrested in 2010 for initiating sex with the victim while she was still asleep. The woman, who reports describe as "physically helpless," gave no consent. She awoke startled and pushed Cesaire off her.

Cesaire, 23 at the time, was arrested and booked in jail. He pleaded guilty, but when the time came for sentencing, Peters said the State Attorney's Office offered probation because the victim said she did not want Cesaire to go to prison.

"Sometimes when we can get (the victims) to cooperate, they start feeling bad," Peters said.

Cappleman acknowledged that many times the victim struggles with feelings of guilt during the process, either because she was drinking or because she consented to some things, such as inviting the man back or kissing him. However, she said, that doesn't mean the victim is responsible for making every decision in the case.

"Sometimes the victim wants that responsibility to be taken off them," Cappleman said. "The prosecutor has to know when it is their time to do that, to say, 'This isn't on you. This is my job.'

"It's not her versus the defendant, it's the state of Florida versus the defendant."

Victoria Jacobsen and Times news researcher John Martin contributed to this report. Contact Caitlin Johnston at cjohnston@tampabay.com or (813) 661-2443. Follow @cljohnst.