Seven people were found shot dead in a house in northern Alabama late Thursday, and authorities said they were searching for the person responsible early Friday.

The Morgan County Sheriff’s Office said deputies and police responded to an emergency call reporting gunshots at about 11:20 p.m. Thursday in Valhermoso Springs, near Huntsville, Alabama. They found seven adults dead and began investigating the case as a homicide, the sheriff’s office said on Twitter.

The department said that there was “no immediate threat to the public in the area,” and that the crime scene unit of the nearby Madison County Sheriff’s Office and the FBI’s violent crimes task force were assisting.

Mike Swafford, spokesman for the sheriff’s office, said today that authorities believe that the shooting was carried out by at least one person who then fled the house.

“We do believe them to have left the area,” he said. “We believe somebody came to this residence to do ill, did it, and then has left. We believe it is an isolated, and not a spree, killing.”

He said authorities had not identified a suspect.

Swafford said that when police arrived, they found a back bedroom of the house, a single-level, ranch-style residence, on fire, but he said the fire was not being investigated as a cause of the deaths. Authorities entered through the garage, where they found three of the bodies, Swafford said. The cause of the fire was not known, he said.

He declined to say where the other bodies were found and did not identify the victims.

Jeff Chunn, Morgan County coroner, said the dead included four men and three women, and their relationship to one another was not immediately clear. No one else was in the house when authorities arrived, he said.

Valhermoso Springs is an unincorporated community with a population of fewer than 1,000 people, in the north-central part of the state.

Swafford said police had been called to the house in the past to respond to complaints related to drugs, trespassing and other issues. Some of the victims had apparently lived there and “some additional come and go,” he said.

The victims were in their 30s to 50s and had multiple gunshot wounds, he said.

“It is a horrific scene,” he said.