Mathieu's mother, Lynette Shinsato, told Judge Kenneth McHugh how she asked John Mitchell, 25, to be the designated driver on the night of the Oct. 23, 2011 crash, and is struggling with forgiveness after Mitchell tried to trick police into thinking he was not behind the wheel.
"My faith and my belief system have been shaken," Shinsato said. "Will God forgive me for not forgiving the actions of another?"
Mitchell pleaded guilty to negligent homicide, aggravated drunken driving and reckless conduct on Nov. 29 for killing Mathieu and injuring another passenger. Mathieu was pronounced dead at the scene of the crash, after Mitchell's 2006 Honda Civic went off of Old Manchester Road in Derry about 1:50 a.m., struck a tree and rolled over.
Assistant County Attorney Brad Bolton argued for a six- to 12-year sentence, saying the broken promise to Mathieu's mother, and Mitchell's claim of not being the driver warranted a longer-than-average prison term.
"That kind of shows you something - what type of character, what type of man he is," Bolton told McHugh in Rockingham County Superior Court.
Mitchell climbed into the back seat and maintained - even while at the hospital - that someone else drove the vehicle, Bolton said.
Another passenger, Brooke Scott, 20, was injured during the crash.
Anthony Mathieu was one of three brothers who served in the military during the wars in Afghanistan and Iraq. A 2005 graduate of Memorial High School in Manchester, Mathieu enlisted in the Marines and served two tours of duty in Iraq between 2007 and 2008.
He had been out of the service for two years, going to college at Southern New Hampshire University and working at his family business, Capital Auto Auction in Manchester, at the time of the crash, according to his mother.
Mitchell turned to Shinsato in court and apologized for his actions, saying she and Mathieu had been like a second family to him.
"To say I left a brother behind, I can't refute that," he said, "but I loved Anthony, no matter what my poor judgment shows. For the rest of my life, I will love him."
McHugh spoke about the challenges he has faced in crafting sentences for negligent homicide cases during his 35 years on the bench, especially when there was no intent to end someone's life.
He said if he knew that a 50-year sentence would bring Mathieu back, "I would impose that sentence. That would probably be true justice."
McHugh said while a four-year minimum might sound like a light punishment to some, "Mr. Mitchell will be associated with a whole of bad people. It's not a lifestyle he is used to."