CORRECTION: In an earlier version of this report, the status of a protective order was misstated. A former Oklahoma student filed a petition asking for a protective order. A hearing is scheduled for next week.

NORMAN, Okla. — No charges will be filed against Oklahoma running back Rodney Anderson, who was accused of rape by a former Oklahoma student, after what the district attorney described as a “thorough investigation.”

“Definitely charges are not warranted under these circumstances,” said Greg Mashburn, the Cleveland County district attorney.

Anderson, a redshirt sophomore, emerged during the season as Oklahoma’s top running back. He led the Sooners in rushing.

Earlier this month the former Oklahoma student, 23, who alleged Anderson raped her Nov. 16 after they had met at a bar, filed a petition asking for a protective order. Anderson passed a polygraph test last week at the request of his attorney. Retired FBI polygraph examiner Bill Brown reported Anderson “denied the allegations” during a three-hour examination and “was not practicing deception in his replies to relevant questions asked of him on this test.”

Under Oklahoma law, polygraph tests are not admissible in court. Mashburn said it did not play a role in the decision not to pursue charges. But he and assistant district attorney Susan Caswell noted the alleged victim’s changing account, over a course of several weeks, of the encounter with Anderson.

“It’s important to know the whole facts,” Mashburn said. “There are certainly cases where we just simply can’t prove something, so we will decline due to insufficient evidence. In this case, I think it’s important for us to tell the whole story so that people understand the facts that were presented to us through the Norman P.D.’s investigation.”

Anderson’s attorney, Derek Chance, said in a statement the decision not to charge Anderson shows he is innocent. Chance said last week the accuser had gone to police only after Anderson had turned away her requests “to pursue a relationship.”

In the petition for the protective order, the alleged victim wrote: “I remember feeling like I couldn’t get away,” she wrote. “He knows where I live and I’m scared for my safety.”

A hearing for the protective order is scheduled for Monday.

She said they did not have sexual intercourse and said she told police she “did not want the sexual activity … that occurred in the bedroom,” according to Caswell, “but she never communicated with Mr. Anderson in any way to let him know that she did not want (the sexual activity).”

Caswell said police interviewed three of the alleged victim’s friends, who described her as having indicated they’d “had a good time and (the alleged victim) was hoping to have a romantic relationship with (Anderson).”

Caswell said the alleged victim’s friends said about two weeks later, she “was remembering that the sexual contact in the bedroom was not consensual.”

Caswell said police also reviewed text messages between the alleged victim and one of her friends, as well as text messages between the alleged victim and Anderson — described the latter texts as “friendly back-and-forth messages between the two of them.” Caswell said Anderson did not respond to “the last few” texts from the alleged victim.

“Based on all of this information … we determined that criminal charges are not warranted,” Caswell said.

Oklahoma plays Georgia in a College Football Playoff semifinal at the Rose Bowl on Jan. 1. Before the announcement, Oklahoma coach Lincoln Riley told reporters at a previously scheduled news conference Anderson was “still fully on the team” during the process.

“Obviously it’s a serious deal,” Riley said. “Something we take very seriously around here. (The authorities) need to take the proper time to go through everything they have.”

Riley said he told Anderson, “We’re there for you, and we know it’s a tough time. … We’ll let the legal process play out.”

In the petition for the protective order, the alleged victim wrote: “I remember feeling like I couldn’t get away,” she wrote. “He knows where I live and I’m scared for my safety.”

Caswell said: “I don’t believe at this point in time she should have fear.”