A fire at a home in Bar Harbor killed two people and injured two others Sunday morning, according to fire investigators.

All of the victims are believed to be related.

State Fire Marshal Joe Thomas said the 2½-story home on Russell Farm Road collapsed into the basement as a result of the intense blaze, which was reported around 8 a.m.

The collapse forced investigators to bring in an excavator to remove the rubble. Thomas said the bodies of two people, who had been reported missing earlier in the day, were recovered Sunday evening.

The state medical examiner is scheduled to arrive Monday and will conduct a post-mortem examination on the bodies in Bar Harbor.

Thomas said a man in his 80s suffered injuries and was transported to Maine Medical Center in Portland. He did not have any information about the fourth person injured in the fire, but it’s believed that four members of the same family lived in the home.

The Mount Desert Islander, a local newspaper, quoted Sgt. Scott Richardson of the State Fire Marshal’s Office as saying that an elderly woman and her son died in the fire. A second son and the woman’s husband escaped but suffered burns.

The names of the dead and injured won’t be released until Monday at the earliest, Thomas said.

Thomas said that Richardson will continue to investigate the cause of the fire.