Once at the apartment, the teammates said they peeked through Winston's bedroom door and saw the woman having sex with the quarterback. At one point, Casher said he "busted into the room to embarrass Jameis" and the girl yelled at him to "get out."
In a later interview with police, Casher changed this part of his story, saying he went into the room because he hoped the woman would also have sex with him, something he said had happened in the past when he and Winston brought a woman to the apartment.
Casher left the room and was not accused of having sex with the woman, and no other women have made accusations against Casher or Darby.
Meggs' office took over the case last month. Investigators interviewed the accuser, other witnesses and collected evidence before the prosecutor made his decision.
He said the woman's blood-alcohol content at the hospital was .04 and investigators estimated it to be about .10 at the time of the incident, based on the amount of time that had passed. The legal limit to drive in Florida is .08.
They also took DNA from Winston and matched it to DNA collected from the woman's underwear. DNA on her shorts matched her boyfriend at the time.
The accuser's family has said they pushed police to take a DNA sample from Winston earlier in the investigation, only to be told by a police detective that it would alert Winston and make the case public.
The family said the accuser's attorney, Patricia Carroll, was warned by police that Tallahassee is a "big football town, and the victim needs to think long and hard before proceeding against him because she will be raked over the coals and her life will be made miserable."
Tallahassee police have defended their handling of the case.
The alleged victim was an FSU student, but she left school last month as media reports of the case surfaced. Meggs said when his office spoke with the woman last month, she wanted the case to move forward.
At a restaurant on campus, students high-fived one another and did the Seminole's chant and tomahawk chop when Meggs' said no charges would be filed.
"It's been a tough couple weeks," said Justin Savage, a 21-year-old senior sports management major from Fort Walton Beach. "I'm just so grateful. He's just so lovable a guy. You can see him on campus and he'll talk to you, it doesn't matter who you are."
Associated Press writer Kareem Copeland contributed to this story.
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