The 59-year-old actor said via video conference that he forgave the man but didn't want him to receive parole, reported Ace Showbiz.
"I miss her all the time," the Emmy-winning star said.
He told Glenn, "I accept that you live with remorse. But I live with tragedy every day. 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."
Glenn first applied for parole in 2009. In response, Kelsey wrote a letter to the parole board, "She was my best friend and the best person I knew. . . . 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. ... It very nearly destroyed me. When we heard this man might be paroled, the suffering began anew."