MILWAUKEE (CBS 58) -- The case may be closed but Milwaukee County's Transit Union President still has questions about what caused a Milwaukee County Bus to slam into a building on Marquette's campus.

Last week, MCTS released video showing a county bus hitting Johnston Hall. It happened back in May.

According to MCTS, the driver didn't hit the brake and instead hit the gas.

The driver says the bus took off on him.

The Union President, however, says something still doesn't add up.

"And you end up running 38 MPH into a building and you are gonna tell me this man didn't know his foot was on the gas or not, on the gas or the brakes, something happened to that bus," said Transit Union President James Macon.

Several passengers were on the bus when it crashed. They and the bus driver had minor injuries. The University says work on the building should continue through the fall.