A man could spend his life behind bars after he was sentenced for the murder of a man whose family is still searching for closure in what occurred on that day.

Loretta McCoy's son Lamont Smith was fatally shot outside of P.S. 112 in the Edenwald section of the Bronx in May 2014.

Dwayne Reid was sentenced to 25 years to life on charges of murder in the second degree and 10 years on criminal possession of a weapon

Prosecutors say Dwayne Reid rented a U-Haul to Smith to help him move machinery for his T-shirt shop, then shot him in the back and twice in the head at close range.

"I miss him so much, my oldest, my first-born," says McCoy. "The pain -- you can't really describe the pain and nobody would understand unless they've been there before."

Family members still don't have all of the answers they want in the case, including if anything like an argument led to the shooting. It's a big question mark that has torn away at the victim's family, who sat in the courtroom Monday in tears.

Even the judge called it a "highly unusual case." Reid's defense attorney offered no additional insight.

"Here there was nothing, there was no motive, nothing was ever put forward ... it's a mystery," says defense attorney Troy A. Smith.

Reid, who grew up with the man he killed, offered condolences to the victim's family, but he said he could not accept any liability for their loss.