PITTSBURGH (AP) - A McCain campaign volunteer made up a story of being robbed, pinned to the ground and having the letter "B" scratched on her face in a politically inspired attack, police said Friday. Ashley Todd, 20-year-old college student from College Station, Texas, admitted Friday that the story was false and was being charged with making a false report to police, said Maurita Bryant, the assistant chief of the police department's investigations division. Police doubted her story from the start, Bryant said. Todd, who is white, told police she was attacked by a 6-foot-4 black man Wednesday night. She now can't explain why she invented the story, Bryant said. Todd also told police she believes she cut the backward "B" onto her own cheek, but did not provide an explanation of how or why, Bryant said. Todd initially told investigators she was attempting to use a bank branch ATM when the man approached her from behind, put a knife with a 4- to 5-inch blade to her throat and demanded money. She told police she handed the assailant $60 and walked away. Todd told investigators that she suspected the man then noticed a John McCain sticker on her car, became angry and punched her in the back of the head, knocking her to the ground and telling her "you are going to be a Barack supporter," police said. She said he continued to punch and kick her while threatening "to teach her a lesson for being a McCain supporter," police said. She said he then sat on her chest, pinned her hands down with his knees and scratched a backward letter "B" into her face with a dull knife. Todd told police she didn't seek medical attention, but instead went to a friend's apartment nearby and called police about 45 minutes later. The Associated Press could not immediately locate Todd's family. Bryant said somebody charged with making a false report would typically be cited and sent a summons. But because police have concerns about Todd's mental health, they are consulting with the Allegheny County District Attorney. She remained in custody and was awaiting arraignment. Todd worked in New York for the College Republican National Committee before moving two weeks ago to Pennsylvania, where her duties included recruiting college students, the committee's executive director, Ethan Eilon, has said. Eilon declined to comment on the investigation Friday or to help The Associated Press contact Todd. Earlier Friday, police said they had found inconsistencies in Todd's story. They gave her a lie-detector test, but wouldn't release the polygraph results. Investigators also said bank surveillance photos did not back up the woman's initial story of being attacked at an ATM. Police interviewed Todd after she contacted police Wednesday night and again on Thursday, Bryant said. They asked her to come back Friday, ostensibly to help police put together a sketch of the man. Instead, detectives began interviewing her. "They just started talking to her and she just opened up and said she wanted to tell the truth," Bryant said. Bryant said it doesn't appear that anyone else put the woman up to the false report. Police suspected all along that Todd might not be telling the truth, starting with the fact that the "B" was backward, Bryant said. "We have robbers here in Pittsburgh, but they don't generally mutilate someone's face like that," Bryant said. "They just take the money and run."