COLUMBUS, Ohio (AP) – Ohio State police say the attacker on campus purposely drove over a curb and into pedestrians and then got out of the vehicle and began stabbing people with a butcher knife.

Police Chief Craig Stone spoke early Monday afternoon at a news conference.

Authorities also said police believe that there was only one attacker. Ohio State said earlier that the suspect had been shot and killed.

The university had sent out a series of tweets at around 10 a.m. Monday saying there was an active shooter on campus and that shooters should run, hide or fight. About an hour and a half later, the university said a shelter-in-place warning had been lifted and the scene was secure.

Authorities said later that it doesn’t appear that the suspect used a gun in the attack.