Gunman Kills Adults and Children at Billings Home

"The initial investigation shows that this event started as a family disturbance and was not a random act of violence where the parties were unknown to each other," the Yellowstone County Sheriff's Office said in a statement, adding that "there is no further danger to the public."

Billings Fire Chief Matt Hoppel said crews were slowed getting water to the fire. "The delay in limited access presented significant challenges, fire conditions continued to worsen, and the residents ultimately became ... consumed by fire," he said at Monday's news conference. Officials said firefighters may have faced water access issues and fewer hydrants than would be ideal.

"First and foremost, the Billings Police Department extends our deepest condolences to everyone affected by this awful tragedy," Sgt. Jeff Stovall of the Billings Police Department said in a statement. "Our thoughts are with the families, loved ones, and all those impacted during this incredibly difficult time."

Stovall said some information is being withheld: "We understand there are many questions surrounding this investigation. However, to protect the integrity of the ongoing investigation, there are details we simply cannot release at this time."