Kelsey Grammer has forgiven his sister's murderer but doesn't want him to be freed from prison.

The 'Frasier' actor's beloved sibling Karen was raped and murdered by Freddie Glenn in 1975 and although Kelsey has granted the killer forgiveness, he has repeatedly blocked attempts to have him freed.

Speaking on BBC Radio 4's Desert Island Discs, Kelsey - who has two children with his wife Kayte Walsh - said: ''I have learnt to forgive. I have even told the guy I forgive him, although I don't advocate his freedom. I don't think that is reasonable.

''In a letter to the parole board, I said the punishment shouldn't be worse for the family than it is for the guy that killed the person and that's what this feels like sometimes.''

Karen was just 18 when she was murdered in 1975 and the following year Glenn was convicted of her murder and those of two other victims selected at random.

Glenn was 18 when he committed the murder and he was given a death sentence, which was later overturned on appeal.

He was granted the right to seek parole after 30 years but in 2009, Kelsey, 62, wrote a letter of objection to the parole board.

He said: ''She was my best friend and the best person I knew. She had so much to live for. I loved my sister, Karen. I miss her. I miss her in my bones.

''I was her big brother. I was supposed to protect her - I could not. I have never gotten over it... It very nearly destroyed me.''

Karen's murder came seven years after Kelsey's father Allen was shot and killed by intruders at his home.