The man accused of killing an Ontario Provincial Police officer in a shootout has died in hospital from injuries he sustained in the incident.

Fred Preston, 70, had been charged with first-degree murder in the death of Const. Vu Pham, a 37-year-old father of three who was gunned down on Monday after pulling over a truck on a rural road in southwestern Ontario.

When another officer arrived at the scene, there was an exchange of fire and Preston was shot.

Police say Preston had been in critical condition in the London Health Sciences Centre-Victoria Campus. His brother Alex said he had been in a coma and on life support, with a bullet in his brain.

Ontario's Special Investigations Unit confirmed Preston's death.

Originally from Sundridge, Ont., Preston was a retired logger and a former local politician described as an avid hunter.

He was also charged with attempted murder in connection with a second, unnamed officer.

Meanwhile on Thursday, hundreds of people gathered at a funeral home in the southwestern Ontario town of Wingham to mourn Pham's death.

"It's an overwhelming tragedy," Pham's adoptive brother Mike Thompson said.

"Every day we wake up thinking we're going to live to see the end of the day and our loved ones, we're going to see them again and it's going to be soon," Thompson said. "You never anticipate that this is going to happen."

Before the visitation began, about 100 people had already lined to pay their respects.

Originally from Vietnam, Pham was taken in as a boy by a southwestern Ontario pastor named Dan Thompson. The family later moved to northern Ontario.

In what appeared to be a coincidence, Pham grew up in Sundridge, the same town Preston was from, although the shooting took place some 375 kilometres from that community.

As a child, Pham even attended the same church as Preston, according to a friend of the accused.

A full police funeral will be held for Pham on Friday afternoon. Thousands of officers are expected to attend.

Pham is the 104th OPP officer to be killed in the line of duty.

With files from The Canadian Press