April 13, 2010— -- Ben Roethlisberger might have promised to be a role model, but the district attorney who declined to press sexual assault charges stemming from a drunken evening at a nightclub said it was the actions of the Pittsburgh Steelers quarterback, not his words, that would prove it.
"You can do better," Ocmulgee, Ga., Judicial Circuit District Attorney Fred Bright said today on "Good Morning America." "Everybody makes mistakes and life and we all learn from them hopefully."
Roethlisberger, dubbed "Big Ben" by Pittsburgh Steelers fans, had been accused of a sexual assault last month by a 20-year-old Georgia College and State University student who claimed the assault took place in a Milledgeville nightclub.
Steelers' President Art Rooney II said in a statement that his star player would now have to focus on regaining the respect and trust of team's fans and live up to the leadership that is expected of him.
"During the past few weeks, I have met with Ben on a number of occasions, not only to discuss this incident but also to discuss his commitment to making sure something like this never happens again," Rooney said in the statement.
Bright said that due to scant physical evidence and conflicting statements from the student, he could not prove a crime had happened.
"You get a lot of he said, she said," Bright said, "but it's unclear. It's foggy, and I couldn't prove it beyond a reasonable doubt."
The woman, who Bright said told police after the incident she didn't know if they even had sex, wrote a letter asking that Roethlisberger not be charged, but Bright said it made little difference in his decision.
"Without that letter, I still feel we did not have enough to prove him guilty, at least of the charge of rape," Bright said.
Click here to read the lawyer's letter asking for an end to the Roethlisberger investigation.
The student's lawyer, David Walbert, wrote to Bright to say that his client did not want to prosecute because "a criminal trial would be a very intrusive personal experience."
"This decision does not reflect any recanting of our client's complaint, but simply a realistic, personal decision as to what is in her best interests," Walbert wrote.
Pittsburgh legend Terry Bradshaw said Roethlisberger needs to behave from now on.
"In my opinion, he has got to realize who he is," he said. "He is an elite athlete in the National Football League."
Bright made headlines Monday, when, at a news conference, he told Roethlisberger to "grow up."
"We are not condoning Mr. Roethlisberger's actions that night," Bright said Monday. He added, however, "We do not prosecute morals. We prosecute crimes."
During a news conference, Bright spelled out a confusing mix of stories that emerged immediately after the complaint was filed, and said alcohol played a significant role in the night's events.
Student Claims She Told Roethlisberger, 'It's Not OK'
When she was first asked by a police officer if she had been raped, she answered, "No," Bright said, citing police reports. When asked if she and Roethlisberger had sex, she said, "I'm not sure," the district attorney said.
Bright said that when the student was interviewed later, when she was sober, she described a different scene.
"I told him it wasn't OK. We don't need to do this," Bright said she claimed she told Roethlisberger. The DA said she claimed to have tried to leave by exiting a door that actually led into a bathroom. The Steeler star allegedly followed her into the room.
"I still said no. This is not OK with me. He said it's okay. He had sex with me," Bright quoted the woman saying.
The police interview with Roethelisberger quoted him telling police that he tried to send the student away, saying, "I told her she was too drunk to be back here," Bright said.
The police officer who wrote the report concluded, "It is unclear as to what happened due to the …recollection due to her intoxication level."
Immediately after the woman made the allegation, Special Agent Tom Davis of the Georgia Bureau of Investigation said, authorities began reviewing videos from Milledgeville nightclubs that Roethlisberger, 28, visited.
Roethlisberger's lawyer, Ed Garland, has disputed the Georgia assault claim and hired his own team to investigate.
Roethlisberger told police last month that he did not have sexual intercourse with the woman who has accused him of a March 5 assault, according to anonymous sources cited by KDKA-TV.
The sources reportedly told the station that Roethlisberger spoke with Milledgeville police on the night of the alleged assault and admitted sexual contact with the woman but said that it was not consummated. The sources said Roethlisberger told police that the woman slipped and fell afterward, injuring her head, according to KDKA.
It was the second time in a year the two-time Super Bowl champion had been accused of sexual misconduct. Roethlisberger also faces a lawsuit filed in July by a woman who alleged that he raped her in 2008 at a Lake Tahoe hotel and casino, which he has denied. He has not been criminally charged and has claimed counter-damages in the lawsuit.
ABC News' Stephanie Wash contributed to this report.