WORCESTER, Mass. (AP) — Authorities have released the names of the four people who died in a fire at a Massachusetts apartment building last weekend, but the cause of the blaze remains under investigation.

The victims of Saturday’s early morning fire in Worcester were identified by authorities on Wednesday as Joseph Garchali, 47; Christopher Lozeau, 53; Vincent Page, 41; and Marcel Fontaine, 29. Garchali and Fontaine lived in the same unit of the three-story, six-apartment building.

The blaze was reported at about 3:30 a.m. and crews were in the scene within three minutes, acting Fire Chief Martin Dyer said earlier this week. Two victims were found Saturday and two more victims were recovered Monday.

The search was slowed by concerns about the integrity of the heavily damaged structure, including a collapsed roof, and the discovery of several live snakes inside on Sunday, which required the intervention of animal control officers.

Four residents required hospitalization, including one who either fell or jumped from a third-floor window, Dyer said. About 20 people lived in the building.

The investigation remains ongoing with the of the federal Bureau of Alcohol, Tobacco, Firearms, and Explosives.