BUFFALO, N.Y. - John Lennon's killer will seek his freedom this week for a sixth time.A parole hearing for Mark David Chapman, 55, is scheduled at Attica Correctional Facility, the upstate New York prison where he has been held for nearly 30 years.

Lennon's widow, Yoko Ono, said last week she continues to oppose Chapman's release because he remains a potential threat.Chapman has been denied parole five times, appearing before the board every two years since 2000. His next interview could take place as early as Tuesday, Division of Parole spokesman Marc Violette said. He could not be more specific, he said, because Chapman is one of dozens of parolees with interviews scheduled for this week and it is unknown when the two-member panel will get to his.

The former maintenance man from Hawaii is serving a sentence of 20 years to life for shooting Lennon four times outside the ex-Beatle's Manhattan apartment building Dec. 8, 1980. He pleaded guilty to second-degree murder.Ono, 77, said in California last week that she was trying to be "practical" in asking that her husband's killer remain behind bars. She said Chapman might be a danger to her, other family members and perhaps even himself. She did not elaborate after making the comments at a meeting of the Television Critics Association, where she was speaking about a new PBS documentary on Lennon's family and artistic life in New York in the 1970s.

Lennon would have turned 70 this October.At his 2008 parole hearing, Chapman told the panel he was ashamed and sorry for what he had done and had since developed a deeper understanding of the value of a human life.

He said he had been seeking notoriety and fame to counter feelings of failure."I would be something other than a nobody and that was my reasoning at the time," Chapman said, according to the 2008 transcript.

The panel denied release "due to concern for the public safety and welfare," according to its decision.This week's decision will be publicly released once Chapman and registered victims have been notified, Violette said. Hearing transcripts are generally made available about a week later.