The city's police department issued an update today on the investigation into the March 29 fire, saying while fire officials have an area of origin where the fire began, they don't know what ignited it.
Investigators say four boys were driven by a friend from Montague to Charlottetown, where they socialized with other friends at a shopping mall before hanging out at a vacant building.
They say a fire was set at some point that night to keep warm.
The bodies of three teens — 19-year-old Joseph Reeves, 16-year-old Brandon MacKinnon and 15-year-old Kenneth Irving — were found inside.
Another teen was injured and rushed to a Halifax hospital.