He had been due to act as an usher at the Christmas Eve midnight mass at his local church in Montrose, California.
Instead, he drove 40 miles to the small town of Covina where his former in-laws were holding a Christmas party.
But police said he was angry at the terms of a divorce settlement last week which ended an acrimonious marriage that had lasted barely a year.Before he could flee, the vapour seems to have been accidentally ignited and exploded."Mr Pardo was severely injured during that explosion," said a police spokesman."He suffered third-degree burns on both arms, and it also appears that the Santa Claus suit he was wearing did melt on to his body."Bruce Pardo's ex-wife and her parents were among the victims as he stormed through their house firing two semi-automatic pistols.He was ordered to pay £6,000 to his wife Sylvia, 43, who had moved out last spring.Pardo was already behind with maintenance payments to his wife, who had three children from a previous relationship, after losing his job as an aerospace engineer in July.