MONCTON, N.B. - A New Brunswick man who strangled a mother and her 12-year-old son with pantyhose without any apparent motive apologized Tuesday as he was sentenced to life in prison for a crime the judge said "defies comprehension."

Relatives of the victims held onto each other and wept in Moncton provincial court as Raymond White was sentenced after pleading guilty to two counts of second-degree murder in the deaths of Mary Lou Barnes, 37, and Larry Mills Jr.

Their bodies were found in their mobile home in British Settlement, N.B., about 55 kilometres southeast of Moncton, on Nov. 6, 1995.

"A big part of me died that day," said the boy's father, Larry Mills Sr., in a victim impact statement.

"I never got to see him graduate, to marry, or for him to provide me with grandchildren.

"He will remain forever young."

White, 65, was charged with two counts of first-degree murder in April 2010 while serving time in British Columbia for three armed robberies in Nova Scotia. He was transferred to B.C. to be closer to his family.

He initially pleaded not guilty but changed his plea last week after voir-dire testimony into the killings. He won't be eligible for parole for 15 years.

"I'm sorry I dragged this out for 16 years," White told the judge.

"I know sorry doesn't cut it. I wish I had the courage to deal with this earlier."

White has never explained why he attacked the family, said RCMP Sgt. Greg Lupson, one of the investigators who worked on the case.

"Mr. White continues to keep secret what exactly transpired when he entered that trailer on Nov. 5, 1995," Lupson said outside court.

Lupson said White became the prime suspect following a review of evidence in 2008. He said improvements in DNA testing produced results in early 2009 that were able to positively identify DNA from White on the pantyhose that was used to kill Barnes.

Crown lawyer Stephen Holt said both victims were choked to death with pantyhose and suffered blows to their bodies. The boy's hands were tied behind his back, Holt added.

He said the White and Mills families once lived just a few houses away from each other in the nearby community of Wood Point and that Barnes and White's wife worked together at a nursing home in Sackville, N.B.

But beyond that, White did not have any significant relationship with the victims, Holt said.

Judge George Rideout said White's actions were deplorable.

"It is such a senseless crime that defies comprehension," Rideout said.

Barnes and Mills Sr. separated in 1994 after moving to British Settlement. Mills Sr. said he had custody of his son on weekends and dropped him off at the mobile home on the night of the murders.

Mills Sr., told the court that for years he blamed himself, wondering if he could have prevented their deaths.

"I didn't know who else to blame," he said. "I tortured myself with 'What ifs?"'

He thanked investigators for never giving up on the case.

"It's going to be 16 years on Saturday and to have this finally come to an end before the 16th anniversary was a blessing," Mills Sr. said.

"My boy was my idol, but he's with me. He's with me everyday."

Defence lawyer Brian Munro said his client's actions had a devastating effect on the victims' family.

"It was probably the most emotional sentencing hearing I've ever been apart of," Munro said outside court.

"Your heart can't help but bleed for the father of the young son."