Colorado police are investigating a gruesome murder-suicide at a home in the suburbs outside of Denver.

Three people are dead including the shooter, who turned the gun on himself.

The killer and the victims have not been identified, but police say the perpetrator was a man in his 40s or 50s. At least one victim, a man in his 70s or 80s, was related to the shooter, local Fox affiliate Fox KDVR reported.

The other victim was in the same age range.

Murder-suicide in Denver

The details are scarce at this stage, but police say the shooting involved a family dispute. A neighbor told local Fox affiliate KDVR that an older woman had died at the home two weeks ago.

"It's so sad," neighbor Bob Davis said. "The mom died, and it just went downhill from there."

Davis said he believes the son was still living at the home. The people living there had recently had a garage sale - old furniture was left outside at the crime scene, with a sign reading "FREE."

Police were called at 4:25 p.m. Tuesday by a family member who went looking for one of the victims. The family member saw what appeared to be a dead body through a window.

When police got to the house on the 8400 block of Franklin Drive, it was locked. Adams County Sheriff’s deputies forced their way inside and found three male bodies.

Gruesome killings in CO

The police initially said there were four dead bodies before correcting the number to three.

“This appears to be an isolated incident and there is no outstanding danger to the public,” the police said.

This comes days after a woman was killed by her boyfriend in another murder-suicide in Northglenn. The victim, Lucille Ruibal, was a leader in the Latino community.

Aurora police found a 62-year-old woman hacked to pieces in a murder-suicide last month. The victim, housekeeper Elena Vonfeldt, was killed while doing her job at a condo in the area.

Police found her body parts inside the residence and in a nearby dumpster. 

The 30-year-old suspect, Dwayne Anthony Jones Sr., shot himself dead as police entered. The Aurora police said it was one of the most gruesome scenes they have ever encountered.