Investigations into the death of Thornwood High School security guard Richard Cowser, who died while trying to break up a fight on Thursday, are still ongoing. An autopsy on Friday determined that the cause the 54-year-old’s death was inconclusive. Police responded to the suburban Chicago school shortly after the incident and found Cowser unconscious in the hallway.

According to ABC, Witnesses said he and another security guard were trying to break up a fight between two girls, when he fell into a nearby locker and began having trouble breathing. Witnesses are unclear if he was thrown by one of the girls or if he simply lost his balance. He lost consciousness before paramedics could respond and was declared dead shortly after being taken to a nearby hospital.

On Thursday the school released a statement offering condolences to Cowser’s family and said counselors were made available for Thornwood students. Police were interviewing witnesses to piece together what happened and are also reviewing security cameras that may have footage of the incident.

The family of Richard Cowser are surprised at his sudden death, as they the security guard was a body builder that was in amazing shape, and was very healthy. In fact, students at Thornwood High School knew him as “Hulk”, including student Tyshon Boyd, who took a cell phone video of the incident. He said Cowser turned purple after he hit the ground.

“The security guards run over there, trying to break the fight up. He jumped in front of the girls and he just slowly passed out. He leaned over into the locker and passed out,” Boyd said.

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