Investigators found partial human remains on Wednesday during the search for two people who are still unaccounted for following last week's Marshall Fire, which tore through two Denver suburbs and destroyed nearly 1,000 homes.
The remains, which were of an adult, were located about eight miles south of downtown Boulder, according to the Boulder County Sheriff's Office.
Superior Mayor Clint Folsom told FOX 31 Denver on Wednesday afternoon that the two missing individuals were "presumed deceased."
The Boulder County Coroner will identify the remains and release a cause of death.
The fire was ignited shortly before noon on Dec. 30, while kids were out of school and many parents were working from home.
COLORADO SHERIFF: WILDFIRE MAY HAVE DESTROYED UP TO 1,000 HOMES
It scorched about 9.4 acres, destroyed nearly 1,000 homes, and forced about 35,000 people to evacuate.
The blaze was fed by an extensive drought in the Denver metropolitan area and 100-mile per hour winds that whipped through the foothills of the Rocky Mountains.
Investigators are still trying to figure out how the fire started.
COLORADO FIRE SCENE COMPARED TO APOCALYPSE
Boulder County Sheriff Joe Pelle said that land owned by Twelve Tribes, a community described by the FBI as a "cult," is part of the investigation.
"We haven't eliminated or honed in on any one specific thing," Pelle said at a press conference. "It's an open investigation. We're going to do it right. It's going to take some time. You're going to lose your patience because it's going to take a while."
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The Boulder County Sheriff's Office said Wednesday that an investigation is also underway in the 1500 block of S. 76th Street in Superior, about two miles from where the human remains were found.
"This devastation happened quickly and many only had a few minutes to evacuate their homes," Colorado Gov. Jared Polis said in a statement on Wednesday. "Too many Coloradans saw a lifetime of hard work reduced to memories -- first homes, businesses, community gathering places."
Fox News's Adam Sabes contributed to this report.