CONCORD – The chances Christopher Gribble will ever see the outside of a prison as a free man are virtually zero, but he still came to a Concord courtroom on Friday to ask a panel of judges for leniency.

Gribble, now 25 and formerly of Brookline, appeared at a sentence review hearing to argue that his age and lack of criminal history at the time of the Oct. 4, 2009, murder of Mont Vernon resident Kimberly Cates and attack on her then 11-year-old daughter, Jaimie, should have commuted a portion of the 75-year sentence he received in addition to life in prison.

Gribble’s attorney, public defender Donna Brown, said the review was something of an “academic exercise,” since the life without parole sentence can’t be changed, but it was also something Gribble had a right to.

“Ten, 20, 30, 40 years from now, laws might change,” Brown said. “Who knows what the law’s going to be in 30 or 40 years?”

Gribble was convicted of first-degree murder in 2011 after pleading guilty by reason of insanity and sentenced to life in prison without parole.

But he was also convicted on charges of attempted murder, conspiracy to murder, burglary and witness tampering. Hillsborough County Superior Court Judge Gillian Abramson sentenced him to the maximum on all of those charges, each consecutive to one another and the life sentence. It was those sentences Gribble argues are too harsh.

Senior Assistant Attorney General Jeff Strelzin, who led the prosecution of Gribble and co-defendant Steven Spader, objected to any lessening of Gribble’s sentences. He said there were far more aggravating factors that outweigh any consideration Gribble should get based on his age and lack of any other criminal history.

“There were many reasons why those sentences were appropriate,” Strelzin said.

Sentence review hearings are available to anyone convicted of a crime and are a right waived as part of most plea deals. Prosecutors can also apply to the three-judge panel if they feel a sentence is too lenient.

Brown said the panel rarely modifies a sentence in either direction, and the process is set up to catch “outlier” sentences that are excessively harsh or lenient.

Strelzin said the court took the matter under advisement.

Gribble and Spader were convicted of murdering Cates with a machete and knife after breaking into the Trow Road home she shared with Jaimie and her husband, David Cates. Jaimie was injured badly in the attack.

Two other men, Amherst residents Quinn Glover and William Marks, are serving decadeslong prison sentences for their roles in the break-in and attempted cover-up.

A fifth man, Autumn Savoy, of Hollis, pleaded guilty to helping the men try to cover their tracks and providing an alibi for them to police. He was recently denied parole.

Joseph G. Cote can be reached at 594-6415 or jcote@nashuatelegraph.com. Also, follow Cote on Twitter (@Telegraph_JoeC).