NEW BEDFORD, Mass. (WPRI) — A Fairhaven man was sentenced to 12 to 15 years in prison for stabbing another man to death over a backpack in a crime spree that also allegedly included armed carjacking and robbery, the Bristol County District Attorney’s Office announced Tuesday.

Matthew Lariviere, 43, was found guilty of voluntary manslaughter.

Police were called to the area of Nauset Street on the night of Aug. 6, 2019, for a report of a body near the railroad tracks.

The victim, identified as Robert Jones III, was found under a tarp and appeared to have been stabbed at least 137 times, police said.

The man who found the body told police a man named “Matt” who lived in a homeless encampment with him and Jones had confessed to the killing, claiming the victim was trying to steal his backpack.

Police recovered the knife and bloody clothes from the killing.

“The defendant brutally killed the victim, but unfortunately there were no eyewitnesses,” District Attorney Thomas Quinn III said. “The jury found that there was an issue of self defense in the case or some other mitigating factors. I respect the jury’s verdict.”

Just minutes after the initial call, Lariviere allegedly committed a carjacking. Police met with a woman on North Front Street who said a man had approached her with a knife and demanded money, then ordered her to take her infant son out of the car before driving off in it.

Police were able to track the car since the woman’s phone was still inside it. He led them on a brief chase, then crashed near Belleville Avenue and tried to run off, but the officers captured him.

Investigators later learned that between the killing and carjacking, Lariviere also allegedly committed a robbery at knifepoint at a store on Ashley Boulevard, according to police.

Lariviere is awaiting trial on charges of armed carjacking and armed robbery.