A John McCain campaign volunteer admitted Friday she made up a story of being robbed, pinned to the ground and having the letter “B” scratched on her face by a black man in a politically inspired attack, police said. On her third day of questioning, Ashley Todd, a 20-year-old college student from College Station, Texas, “just opened up and said she wanted to tell the truth,” said Maurita Bryant, assistant chief of the police investigations division. Todd could provide no explanation for why she invented the story, police said. The woman told investigators she believes she cut the “B” onto her own cheek, but did not provide an explanation of how or why. Police said the woman reported suffering from “mental problems” in the past, and that they do not believe anyone put her up to the act. She was to be charged with making a false report to police. Authorities hoped to have her jailed and undergo psychiatric evaluation, said police Lt. Kevin Kraus. If she is not ordered held, he said authorities would seek to have her involuntarily committed to a psychiatric institution. Todd, who is white, told police she was attacked Wednesday night by a tall dark-skinned black man wearing patent leather shoes. Race has been a sensitive issue in the campaign, as Democrat Barack Obama would be the first black US president if he wins the Nov. 4 election.