BOWDEN, Alta. -- A man convicted of manslaughter for his role in the shooting deaths of four Alberta RCMP officers near Mayerthorpe has been granted unescorted, temporary absences from prison.

The National Parole Board ruled following a hearing at Bowden Institution on Wednesday that Shawn Hennessey will be allowed out for up to 72 hours at a time over the next six months.

Board spokesman Gary Sears said Hennessey, 34, will have to follow certain restrictions.

"There are three conditions: not to consume or possess alcohol, not to consume, purchase or possess drugs and to avoid negative associates, those involved in criminal activity," Sears said.

Hennessey was sentenced to 15 years in prison, but his jail time was reduced to a little more than 10 years because he pleaded guilty and spent time in pretrial custody.

He and his brother-in-law Dennis Cheeseman gave gunman James Roszko a rifle and ride to Roszko's farm where he ambushed and killed the RCMP officers in March 2005.

The officers were staking out a marijuana grow-op and auto chop shop that had been discovered on Roszko's property when they were ambushed. Roszko killed himself after being shot by another Mountie who had just arrived.

Cheeseman was sentenced to 12 years, but his jail time worked out to just over seven years because of credit he, too, received.

The two unsuccessfully asked the Alberta Court of Appeal and the Supreme Court of Canada to shorten their sentences even more. Their lawyers argued the punishment was vengeful and too severe.

The men said they feared for their own safety and that of their families if they didn't help Roszko. They were turned down at both court levels.

Cheeseman was granted statutory release late last year.

Hennessey is eligible for statutory release on Dec. 29, 2015.