MONCTON, N.B. -- One of the men convicted in the slayings of three people at a McDonald's restaurant in Cape Breton more than 20 years ago has had his application for day parole denied after the Parole Board of Canada concluded that Derek Anthony Wood is still a risk to society.

In a decision dated March 31, the parole board cited a number of reasons for rejecting day parole for Wood.

The board said he has reoffended in a violent manner while in prison, pointing to a 1998 assault against another inmate involving sharpened paint brushes and a sharpened toothbrush and the assaults of two correctional officers in 2006.

"The board is satisfied that by reoffending you will present an undue risk to society and your day parole release will not contribute to the protection of society," the decision said.

The board's decision also said that Wood, now in his early 40s, has been isolated for nearly seven years, has not shown the ability to function in a less restrictive setting and minimizes his responsibility for his status as a maximum security prisoner.

The ruling said while Wood acknowledges that it was his idea to rob the McDonald's restaurant on May 7, 1992, he did not know it would turn violent, indicating his lack of insight into his criminality.

Wood was sentenced to life in prison with no eligibility for parole for 25 years after being convicted of a number of charges including two counts of first-degree murder.

The parole board said inmates serving life sentences with no eligibility for parole for 25 years can apply for day parole after serving 22 years of their sentence.

Wood was an employee of the McDonald's in Sydney River and was the mastermind behind a botched robbery during which three people were killed and one paralyzed. He shot three employees in the head after entering the restaurant with two other men.

Darren Richard Muise pleaded guilty to armed robbery and second-degree murder in the stabbing death of Neil Burroughs, a married father and maintenance worker at the McDonald's.

Jimmy Fagan, 27, another maintenance worker, was shot dead along with 22-year-old shift manager Donna Warren.

Cash clerk Arleen MacNeil was also shot but she survived and is paralyzed.

Muise was sentenced to life in prison with no chance of parole for 20 years. He was granted full parole in 2012.

A third man, Freeman MacNeil, is serving a life sentence with no eligibility for parole for 25 years after being convicted of first-degree murder.