The man who admitted to killing four young men in Pennsylvania had a history of run-ins with the law, including incidents that got him banned at two separate educational institutions. Cosmo DiNardo, 20, was banned from his alma mater, Holy Ghost Preparatory School, as well as Arcadia University, where he was enrolled for a single semester.

DiNardo appeared at an open house at Holy Ghost Preparatory School in October, despite not being invited. School administrators noticed something “off” about his behavior at the event. He soon became disruptive and was asked to leave the campus.

Read: Who Is Cosmo DiNardo? Man Who Confessed To Killing Pennsylvania Men Spoke Of Murder Before

“The behavior was enough for us to be concerned,” school spokesman William Doherty told WCAU-TV Wednesday, declining to go into the specifics of the incident.

The school then filed a police report and called DiNardo’s parents to notify them that their son was banned from the school going forward. The incident was merely the first time DiNardo was forbidden from entering a school.

The 20-year-old attended Arcadia University in Glendale, Pennsylvania for one semester in fall 2015. When he tried to return to the school the next year, administrators told him he was not welcome there and would be trespassing if he tried to enter the campus.

University administrators cited “verbal incidents” and behavior that made people uncomfortable as reasons for DiNardo’s ban from the school, a spokesperson told WCAU. The situation was handled as a public safety issue.

A diagnosed schizophrenic, DiNardo was involuntarily committed to a mental institution at some point in the past, though the timeline and details surrounding the situation remained unclear.

DiNardo and his cousin, Sean Kratz, were charged with the criminal homicide of four young men in Bucks County, Pennsylvania last week. The bodies of Jimi Patrick, 19, Tom Meo, 21, Mark Sturgis, 22, and Dean Finocchiaro, 19, were all found buried on a 68-acre property belonging to DiNardo’s parents. He told investigators he and Kratz killed the men during or after selling them marijuana, though no further motive was discerned.

“I’m not sure we’ll ever know,” Bucks County District Attorney Matthew Weintraub said of the motive.

Read: Cosmo DiNardo Says He Killed Two Others Before Murdering Four Pennsylvania Men

While confessing to the four murders, DiNardo also reportedly told investigators he had killed two other people in Philadelphia when he was younger. Police said they hadn’t yet determined whether there was any truth to the claims, but said they were actively looking into it.

“Given what he was already been accused of, it’s certainly a possibility,” Philadelphia Police Commissioner Richard Ross told WCAU Tuesday. “We would be remiss if we didn’t investigate further. In order for us to lend any credence to it, we would have to talk to him directly. When you’re dealing with someone who is pathological like that, you don’t know where he is coming from.”