Authorities are pointing to a variety of causes that killed five young siblings in a duplex fire last week in north Minneapolis.

The determinations were released Monday by the Hennepin County medical examiner’s office in the deaths from the predawn fire in the upper unit of the duplex at 2818 Colfax Avenue N. The office added that investigators have yet to determine how the blaze began.

Three people escaped the fire and remain Tuesday in the Hennepin County Medical Center: father Troy Lewis, 60, is in satisfactory condition, while daughters Shaca, 9, and Electra, 5, remain in critical condition, a hospital spokeswoman said.

Three of the children died at the scene shortly before 5 a.m.: Gwendolyn, 18 months, and Christopher, 8, both from smoke inhalation and carbon monoxide poisoning; and Mary, 6, from smoke inhalation and burns.

The other two children died about an hour later at North Memorial Medical Center: Troy, 3, from smoke inhalation and carbon monoxide poisoning; and Fannie, 4, from inhaling “products of combustion” from the fire, the medical examiner’s office report read.

Substantial efforts are underway to assist the surviving family members and to help fund funeral expenses.

Minneapolis MAD DADS has organized a relief effort, with clothing a priority. Items can be delivered to the Shiloh Temple at Bloomington Avenue S. and E. 27th St. in Minneapolis. The Minneapolis Federation of Teachers also is receiving clothing, toiletries and household goods at federation headquarters, 67 8th Av. NE.

Financial contributions are being accepted at any BMO Harris Bank branch to assist the Garrett family, which lived downstairs in the duplex. Donations should be labeled “For benefit of the Garrett family.” A way to contribute money for the Lewis family has yet to be finalized.