KELSEY GRAMMER traumatized by the brutal 1975 murder of his sister.

Kelsey told CNN’s Piers Morgan that his life went into a tailspin "for at least 20 years" because he felt responsible for the tragedy.

In 1975,  Kelsey’s teenage sister Karen bled to death after three thugs molested her, slashed her throat and dumped her corpse by the side of a road in Colorado Springs, Colorado.

Kelsey was 20 at the time of his beloved sibling's murder.

 “When Karen was killed. It sent me into kind of a tailspin,” he said.

“It was a horrible nightmare for her.

“I, being the big brother that I had been, thought that I had some responsibility for that and that haunted me for at least 20 years — that notion."

As The ENQUIRER reported previously, in 2009 Grammer wrote an impassioned letter to the parole board to make sure the convicted killer remained behind bars.

He was denied parole.