PITTSBURGH — 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 what she had said was a politically inspired attack, police said yesterday.

Ashley Todd, a 20-year-old college student from College Station, Texas, admitted yesterday that the story was false, said Maurita Bryant, the assistant chief of the police department's investigations division. Todd was charged with making a false report to police, and Bryant said police doubted her story from the start.

Dressed in an orange hooded sweatshirt, Todd left police headquarters in handcuffs late yesterday.

Todd was awaiting arraignment yesterday on the misdemeanor false-report charge, which is punishable by up to two years in prison. She will be housed in a mental health unit at the county jail for her safety and because of "her not insignificant mental health issues," prosecutor Mark Tranquilli said.

Todd initially told investigators she was attempting to use a bank branch ATM on Wednesday night when a black man approached her from behind, put a knife blade to her throat and demanded money. She told police she handed the assailant $60 and walked away.

Todd, who is white, told investigators she suspected the man then noticed a John McCain sticker on her car. She said the man punched her in the back of the head, knocked her to the ground and scratched a backward letter "B" into her face with a dull knife.

Police said Todd claimed the man told her that he was going to "teach her a lesson" for supporting the Republican presidential candidate, and that she was going to become a supporter of Democratic candidate Barack Obama.

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.

"We are as upset as anyone to learn of her deceit, Ashley must take full responsibility for her actions," College Republican National Committee spokeswoman Ashley Barbera said in a statement.