Investigators are still trying to find out why Thomas Cowan went to Sullivan Central High School and pulled a gun on the principal.
Authorities say Cowan was no stranger to police.
Kingsport police say they've had nearly a dozen encounters with Thomas Cowan over the last decade.
In some of those cases he made complaints to the police department, but Deputy Chief David Quillin says Cowan was the one in trouble at least three times in the past.
According to police, Cowan was arrested in 2000 after he carried a gun into the Justice Center. Officers say they encountered him again in March of 2001.
"In that instance we served a warrant on him for stalking an individual and then later a warrant on him for stalking an individual, and then later in 2001 he was a suspect in a trespassing instance at a local convenience store," said Deputy Chief David Quillin with the Kingsport Police Department.
Police say Cowan has a relative who works at Sullivan Central High School. However, it's still unclear whether that played a role in his being at the school Monday morning.