BOULDER, Colo. — The Boulder Police Department is investigating why a stun gun didn’t work properly when officers tried to subdue an armed college student Monday night.

Samuel Forgy, 22, was nude and high on LSD when officers approached him, Boulder police said. Forgy wouldn’t listen to officers when they tried talking to him. Instead, he tried to attack them with a hammer, investigators said.

When the stun gun didn’t work properly, police said they had no choice but to open fire. Forgy was pronounced dead at the scene. A Boulder police spokeswoman would not say how many times Forgy was shot.

“This was a rapidly evolving situation,” Sarah Huntley said.

People who knew Forgy told officers he was high on LSD. The Boulder County Drug Task Force said anytime someone is naked and attacking people, there’s a good chance they’re hallucinating.

LSD alters a person’s mind and allows them to see and experience things that don’t actually exist.

“It could work really against the person or open new vistas,” said Daniel Minerva, a drug counselor with the Addiction Exchange in Boulder.

It’s hard to tell what sort of experience Forgy had on LSD. While LSD is a consistently used drug in Boulder County, it’s not as popular as heroin.

Arapahoe House, a drug treatment center on the Front Range, said this past year it only has seven submissions for LSD compared to 1,200 submissions for heroin.