LOUISVILLE, Ky. (WDRB) -- Police in St. Matthews have arrested a man after he allegedly attacked a security guard at Jeffersontown High School.

According to the arrest warrant, it happened on March 17. That's when police say William E. Thomas III showed up at the school to confront a student he believed stole a gold chain from his son, who is a student at the school. Police say Thomas was observed by school staff with his son on the bus loading dock as his son pointed out a group of students.

Thomas allegedly confronted the students "as if he wanted to fight."

That's when police say school security stepped in, asking Thomas to back away from one of the students. When Thomas refused and again approached a student, the security guard "grabbed Thomas and tried to restrain him."

Thomas struggled with the security guard, police say, they both fell to the ground, and the security guard hit his head on the pavement. The security guard was finally able to restrain Thomas, and Jeffersontown Police were called. Thomas was allowed to leave after officers took his information.

The security guard was taken to the hospital and treated for head wounds, including a concussion, laceration and a large knot on the back of his head.

An arrest warrant was issued for Thomas, and he was taken into custody on May 21.

He's charged with assaulting a school employee and criminal trespassing.

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