(CNN) -- A Colorado police dispatcher listened helplessly early Tuesday as a man apparently killed at least one other person and then himself, part of an apparent murder-suicide that left four people dead, a sheriff's office spokesman said.
Weld County Sheriff's spokesman Tim Schwartz said the call came in around 4 a.m. (6 a.m. ET). In the call, a woman gives an address in Longmont, Colorado, then says "no, no, no," followed by what sounded like a series of gunshots.
A man then picks up the phone and tells the dispatcher he is going to kill himself, according to Schwartz. The next thing the dispatcher heard, Schwartz said, was another gunshot.
Weld County officers who responded to the scene called in a SWAT team, who entered the house and found four people dead.
Investigators had not identified the dead, but said two of the people involved were men and two were women. All were believed to be adults, Schwartz said. No one else was home, he said.
CNN's Karan Olson contributed to this report.