Police have released photographs of a 28-year-old gunman, as they seek witnesses to Monday's shooting rampage in Langley, B.C., that left two victims dead and two wounded.

The photos show Jordan Daniel Goggin wearing two outfits during the course of the shootings, which began around midnight and lasted nearly six hours before police shot and killed him.

The Integrated Homicide Investigation Team describes Goggin as a six-foot-one Caucasian man, weighing 150 pounds, with light brown hair and a slight goatee.

He is seen wearing a black T-shirt and board shorts, before police say he changed into brown overalls and a camouflage T-shirt.

Police say Goggin, from Surrey, B.C., was driving a white Mazda four-door sedan.

IHIT says one witness has come forward and is hoping others come forward as police try to construct a timeline of the shootings.

"We are trying to identify additional witnesses to aid in victimology and assessing motive," said Sgt. David Lee spokesman for IHIT. "There may be people out there who remember seeing Goggin, his Mazda, or may have even encountered him."

The shootings, that police have said involved "transient victims", left two male victims dead, another with non-life-threatening injuries, and a woman in critical condition.

Prime Minister Justin Trudeau issued a statement on Twitter saying he's "horrified" by the shooting.

The post said his heart breaks for the victims' loved ones and communities, and his thoughts are with the injured.