Newtown Alum Bruce Jenner Mourns Sandy Hook Shooting: "This Is Unimaginable"

Olympian's sister went to Sandy Hook Elementary School, where 20 children were killed last week

The horrific tragedy that unfolded in Newtown, Conn., last week hit close to home for Bruce Jenner.

"Not in a million years would you ever think that this quiet little town would have such a terrible, terrible tragedy happen there," the Olympic gold medalist and graduate of Newtown High School exclusively tells E! News in reaction to the shooting at Sandy Hook Elementary School that left 20 children dead. "You just can't believe it."

Jenner's sister attended kindergarten at Sandy Hook, and Newtown High's stadium bears his name.

Jenner says that he first heard about the shooting on TV, like most everybody else, and it took him a moment to realize that it was Sandy Hook the newscasters were talking about.

The E! star's son Burt is named after his younger brother, who was killed in a car accident not long after Jenner won his gold medal at the 1976 Summer Olympics. He says the loss of his sibling was "devastating," but that what happened to those children is "unimaginable."

He's been in touch with his sister and his mom, and they were both as shocked and saddened as he was by the tragedy that unfolded.

Says Jenner: "I just get mad inside at humanity sometimes and how a twisted mind can be so evil."

(Originally published Dec. 18, 2012, at 7:21 a.m. PT)