SEATTLE (AP) _ Investigators believe the fatal shooting at a shipyard this week was sparked by a grudge against one of the two men who died, according to unidentified law enforcement officials who spoke to The Seattle Times Friday.

The conclusion was drawn from evidence at the scene and leads, the sources, who spoke on condition on anonymity, told the newspaper.

A gunman who has not yet been caught walked into the shipyard office Wednesday morning and fatally shot Peter Giles, 27, and Russell James Brisendine, 43. Two others _ a new employee and a fisherman _ were wounded in the attack. The sources, who are familiar with the investigation, did not say who was believed to be targeted.

Police spokeswomen would not comment on the report and said they knew of no new developments.

In a news conference Thursday, Police Chief Norm Stamper described the attack as ``a deliberate, calculated act'' but would not comment on a motive.

The gunman was described as a man in his 30s with curly brown hair and a mustache. He wore a baseball cap, sunglasses and a dark overcoat over camouflage clothing.