Delaware prosecutors said Thursday that they will not file criminal charges against NASCAR driver Kurt Busch following allegations of domestic violence against his ex-girlfriend.

NASCAR officials indefinitely suspended Busch last month after a Delaware Family Court judge said the former champion almost surely choked and beat Patricia Driscoll inside his motorhome at Dover International Speedway last fall.

But the Delaware attorney general's office said Thursday that there was not enough evidence to bring criminal charges.

"After a thorough consideration of all of the available information about the case, it is determined that the admissible evidence and available witnesses would likely be insufficient to meet the burden of establishing beyond a reasonable doubt that Mr. Busch committed a crime during the September 26th incident," the attorney general's office said in a prepared statement.

Jim Liguori, a local attorney for Busch, said the driver, known in NASCAR circles as "The Outlaw," was thankful.

"All along, he knew he was going to be exonerated," Liguori said. "The Department of Justice really did the right thing after considered review."

"She absolutely tried to destroy him in the press, or tried to," Liguori added, referring to Driscoll. "But the truth wins out, and the truth is its own defense."

Driscoll did not immediately respond to email and telephone messages seeking comment.

Driscoll said Busch assaulted her in September after she drove from her Maryland home to Dover to check on Busch after receiving a series of disturbing texts.

Busch and his attorneys have portrayed Driscoll as a scorned woman who set out to destroy Busch's career after he ended their relationship.

Driscoll said she and Busch argued in the bedroom of the motorhome before he grabbed her by the face and neck and slammed her head against a wall three times.

Driscoll filed charges in November, saying she feared the incident might affect an ongoing child custody battle with her ex-husband.

Driscoll also filed for a no-contact order in November, which was the subject of four days of hearings in December and January. The Family Court hearing featured testimony from Busch and others who said Driscoll told stories of being a covert operative for the federal government and a trained assassin.