By Mike Cooper

ATLANTA (Reuters) - National Football League star Ben Roethlisberger will not be charged with a crime stemming from a sexual assault allegation, a prosecutor in Georgia said on Monday.

The announcement by District Attorney Fred Bright followed a report last month by a 20-year-old college student that the Pittsburgh Steelers' quarterback sexually assaulted her after an encounter at a nightclub in the central Georgia city of Milledgeville.

"The sexual allegation against Mr. Roethlisberger cannot be proved beyond a reasonable doubt," Bright said. "Therefore, there will be no arrest made, no criminal prosecution."

The accusation came after a night of bar-hopping, and Roethlisberger and his accuser had both been drinking alcohol, Bright said. He said the pair had conversations "of a sexual nature."

But he said a doctor who examined the woman found no evidence of semen or discharge. Subsequent testing found human male DNA, but the sample was too minute to reveal a profile, he said.

"I'm happy to put this behind me and move forward," Roethlisberger said in a statement.

"I am truly sorry for the disappointment and negative attention brought to my family, my teammates, coaches, the Rooneys (Dan Rooney owns the Steelers) and the NFL," he said.

Bright said there were still significant questions about what occurred and, "everyone agrees that the victim was highly intoxicated. In addition, he said, he had met with the accuser and her attorney and she did not want to prosecute.

"We are not condoning Mr. Roethlisberger's actions that night but we do not prosecute morals, we prosecute crimes." Bright said.

Roethlisberger, 28, is one of the top-rated quarterbacks in the NFL, leading the Steelers to Super Bowl victories in 2006 and 2009.

He is the youngest quarterback to have won the Super Bowl, his first win coming in just his second professional season.

(Editing by Peter Cooney)