Erik Menendez has been denied parole, nearly 40 years after he and his brother killed their parents inside their Beverly Hills mansion.

The 54-year-old appeared before the California Board of Parole Hearings on a live feed from the Richard J Donovan Correctional Facility in San Diego on Thursday, after a judge decided to reduce his and his brother Lyle's sentences of life in prison without the possibility of parole to 50 years to life.

The two have been campaigning for years, but the board told Erik he would be denied parole for three years due to his behavior in prison.

They brought up prison reports of fights and other violations dating back to 1997, including drug and alcohol use, instances in which he was found with a contraband cell phone and even allegations that he helped a prison gang in a tax fraud scheme in 2013, the LA Times reports.

'Contrary to your supporters' beliefs, you have not been a model prisoner and frankly we find that a little disturbing,' the board said, according to reporter Brian Entin.