A Southern Illinois man is in under arrest for terrorism charges.

Keaun L Cook was arrested Wednesday on preliminary charges of providing material support for terrorism and making a terrorist threat.

At a news conference Thursday, Madison County’s state’s attorney, Tom Gibbons, described Cook as a dangerous man who had deliberate plan to cause a “mass casualty event” at one or more locations in the county. He declined to specify which terrorist group Cook had allegedly been in contact with, but said they weren’t local.

County Sheriff John Lakin said authorities learned of the threat in August when deputies did a welfare check at the home of Cook’s grandmother.

There, authorities say, someone reported Cook’s verbal threats.

Cook’s grandmother says that her grandson struggles with paranoid schizophrenia and that he had spent more than 300 days in isolated confinement at a county detention center, during which his condition went untreated.

He is currently being held at the Madison County jail on $150,000 bond and as of Friday did not have a lawyer.