A St. Paul house fire that killed four children and seriously injured more family members was likely started by an unattended candle, the St. Paul Fire Department said Thursday.

The fire on Jan. 3 burned the house of Pa Cheng Vang and his wife Ker Lor, and killed four of their children: 5-year-old twin daughters Ntshiab Si and Siv Ntshiab, 4-year-old son Mauj Tshau Ntuj, and 1-year-old son Mauj CagTxuj Vaj.

The finding that a candle caused the fire is based on a preliminary investigation report and is not final, the department added.

Firefighters were alerted around 1:30 a.m. to the blaze in the small house in the 1200 block of N. Arkwright Street and arrived in less than 3½ minutes, Deputy Fire Chief Roy Mokosso said.

Crews found Vang's wife and six children inside. All were unresponsive when emergency crews arrived. Investigators said they do not believe the blaze's origin is suspicious.

The fire department will host a news conference at 9 a.m. Saturday at its headquarters, 645 Randolph Av. in St. Paul.

There will be a vigil to support the family at 1 p.m. Saturday.

"Let us collectively help to provide support and comfort for Pacheng and his beautiful beloved angels during this difficult time," a Facebook post for the event reads.

The vigil will be held at the Vang children's school, the American Indian Magnet School at 1075 E. 3rd St. in St. Paul.

"I [am] the only one that support my whole family with shelter and foods. We have [no] life insurance cover[age] for our kid due to [lack] of income," Vang said in an online fundraiser.