Oregon State University authorities, police and the FBI investigated threats of a campus shooting on Tuesday afternoon, after several alarming Tweets were brought to the university's attention.

“We had no knowledge of anyone being on campus with weapons or acting violently in any way,” says university vice president Steve Clark. “We were aware that there were social media posts that were actively being investigated while they were being made.”

No campus buildings were placed on lock down because of the threat.

University officials confirmed that several Tweets that threatened a mass shooting led to the investigation.

Oregon State Police arrested 22-year-old Corvallis resident Christopher Adam Strahan for posting the tweets. He was booked on a disorderly conduct charge.

Clark says Strahan has no known affiliation with the university, and is not currently a student, staff or faculty member.