ANN ARBOR - A woman who was walking across the University of Michigan’s campus was sexually assaulted Tuesday night, the same time as the “Naked Mile.”

She was not participating in the annual nude celebration that marks the end of spring semester classes, said Ann Arbor Police Sgt. Andrew Zazula.

Police suspect the assault was tied to the event and are searching for the assailant.

Such attacks were one reason the city and university sought to end the event, which has been a tradition since 1986. Over the years it has gained notoriety, drawing sometimes unruly crowds.

Two dozen participants and approximately 7,000 on-lookers attended the event, said Diane Brown, university public spokeswoman. In years past, it has drawn hundreds of runners and thousands of spectators.

Ann Arbor and university police arrested a total of 12 people for violations from indecent exposure to drug possession. Police intervention teams discouraged naked runners and the clothesless joggers were given a chance to cover up and avoid arrest.

“This event needs to be ended because it has such a high probability of danger,” Brown said. “Students are starting to hear the message and are very concerned about the crowds and exploitation that this has attracted.”

THE ASSOCIATED PRESS