BARRIE, Ont. -- Police say almost 60 people ordered from their homes in Barrie because of the discovery of explosives may not be able to return until early next week.

Investigators continue to discover explosive devices at a house in the neighbourhood -- Barrie police Sgt. Tim Conroy says at least one device was found today.

Conroy says it's unlikely the teams will be finished by Sunday as they scour for more devices.

Police and explosives experts began searching the residence Thursday and have found at least five homemade explosive devices as well as firearms and unidentified chemicals.

The police evacuation order has displaced 57 people from 22 homes nearby.

Police say the home belongs to two men who are suspects in the 1978 slaying of a man.

Donald Feldhoff, 54, has been charged with first-degree murder in the slaying of Michael Traynor, while his 75-year-old father William has been charged with being an accessory after the fact.

Conroy said the police teams have not yet determined the home is clear of dangerous devices and chemicals.

"They have to move cautiously and slowly," Conroy said.

"We can't stop looking once we find one (explosive device)."