State fire investigators were working Saturday to establish the cause of a Lake Elmo house fire that displaced six people — two adults and four children — the previous day.

Firefighters were called to the house in the 10000 block of 57th Street N. about 4:40 a.m. Friday and arrived to find the house “fully involved in fire,” the town’s fire chief, Greg Malmquist, said via e-mail on Saturday. The home’s occupants got out safely, but two pets died in the fire, Malmquist said.

Firefighters from five other departments — Oakdale, Mahtomedi, Stillwater, Bayport, Lower St. Croix Valley and Woodbury — battled until the early afternoon to extinguish the flames, officials said.

By then, the house was almost gutted — “a total loss,” said Sgt. Larry Osterman of the Washington County Sheriff’s Office.

Sheriff’s deputies pulled up to the scene five minutes after the 911 call was placed to find the home swallowed by fire, Osterman said.

A cause had not been determined by Saturday morning,.

The seven-bedroom, nine-bathroom home was built in 2013, according to online property records.

The Red Cross assisted the displaced family, a spokeswoman confirmed on Saturday.