The "Frasier" star testified against proposals to release Freddie Glenn via video conference at his parole hearing on Tuesday.
Grammer told prison officials at the Buena Vista Correctional Facility in Colorado that he has forgiven the convict for abducting, abusing and killing his younger sister Karen in Colorado Springs back in 1975, but could not support his bid for freedom.
The actor told Glenn, "I accept your apology. I forgive you. However, I cannot give your release my endorsement. To give that a blessing would be a betrayal of my sister's life."
Parole board members reviewed the case overnight and on Wednesday announced Glenn's request to walk free from his life sentence had been denied.