COLORADO SPRINGS, Colorado (CNN) -- As hundreds of firefighters began to get the upper hand on a huge blaze near Colorado Springs, Colorado, investigators stepped up their probe into the cause of the most destructive wildfire in the state's history.
The 16,000-acre Black Forest Fire, which was 65% contained Sunday, is now considered a crime scene, according to El Paso County Sheriff Terry Maketa, who said it will be some time before residents will be allowed to go home permanently.
"We have a crime scene in there. We have fire in there. We have downed power lines in there. We have trees falling each time there is a gust of wind," he said, adding he was calling it a crime scene until proven otherwise.
The sheriff said the Bureau of Alcohol, Tobacco, Firearms and Explosives has been called in, along with state authorities.
"It has far expanded beyond just my arson investigator," he said Sunday. "We have brought experts in to give us the greatest possible chance to not only determine the cause, but whether there was criminal intent or not."
No explanation was given for the crime scene designation.
The weather cooperates
The revelation comes as fire teams made significant progress against the flames northeast of Colorado Springs over the weekend, with containment growing from 5% to 65% in just a few days time.
And the forecast continues to look promising.
The National Weather Service says highs will be in the upper 70s through Tuesday, with up to a 40% change of rain each day and light winds.
Temperatures in the 90s, little rain and blustery winds fueled the Black Forest Fire in its early days.
In the first few days after the fire broke out, crews had zero containment on the Black Forest Fire as it ravaged woods and neighborhoods. County spokesman Dave Rose told CNN it appeared to be the most destructive in the history of Colorado -- a state that's all too familiar with devastating wildfires.
As of Sunday, authorities had counted 483 structures lost due to the blaze that started Tuesday, CNN affiliate KUSA reported. Two people had died.
The speed and intensity of the flames created a pattern where, for the most part, homes either were destroyed or escaped unscathed, Maketa explained over the weekend.
In some areas, he said, there's no number on the house, no mailbox and virtually no other signs that someone lived there just a few days ago.
"You can't even recognize where there was a house or some other kind of structure," the sheriff said Saturday. "That is the level of incineration and destruction that took place in some areas."
Other Colorado fires
Firefighters also made significant progress on the Royal Gorge Fire, southwest of Colorado Springs, announcing it was 100% contained Sunday night. The fire scorched more than 3,200 acres, including a beloved carousel and at least 20 buildings, according to Gov. John Hickenlooper.
"It's burned to a cinder," he said Friday of the area.
The governor has declared a disaster emergency in Rocky Mountain National Park, northwest of Denver, due to the Big Meadows Fire that's burned hundreds of acres there.
The latest flare-up is the Ward Gulch Fire in the western part of the state. No structures are reported destroyed yet in that blaze, but gusty winds, low humidity and warm weather have firefighters on edge.
While all those fires pose dangers in their own ways, the Black Forest Fire is still by far the biggest and the most dangerous, which is why thousands in that area remain evacuated, their homes in areas where it is too perilous to return.
Said Maketa: "We're hoping to gain inches each day to get people's lives back to normal, where it can be returned to normal."
CNN's George Howell reported from Colorado Springs, and Ed Payne wrote in Atlanta. CNN's Steve Almasy and Greg Botelho contributed to this report.