About 60 neighbours were evacuated from nearby residences last Thursday after police found explosives and unknown chemicals in the home.
The residents are expected to be out of their homes for the rest of this week and Const. Angela Butler said police have no idea when they will be able to give the all-clear.
Investigators released photographs Tuesday of some of the devices and weapons found in the home, and of a basement room filled with boxes and jugs of chemicals.
Experts combing through the home have described the explosives as pipe bombs and improvised explosive devices, Butler said Tuesday night.
Some of the devices were found in holes drilled in walls and were wired so that they could be detonated remotely, Butler said.
The city of Barrie approved a permit in 1984 to the owner of the home for a fallout shelter, which Butler said has been divided into two rooms.
Police plan to clear the house before turning their attention to the bunker, Butler said.
Among the weapons found in the house were three rifles and two shotguns and "thousands of rounds of ammunition," she said.
Donald Feldhoff, 54, was charged with first-degree murder after turning himself in to police last week. His 75-year-old father William has been charged as an accessory after the fact.
The father and son are charged in connection with the slaying of 26-year-old Michael Traynor.
The investigation into Traynor's death went cold shortly after his body was found in a wooded area in October 1978.
Police said he had been bound and shot multiple times in the chest.
(CHAY, The Canadian Press)