(AP) - Investigators are getting closer to pinpointing where Colorado's most destructive wildfire started and that should help allow residents of the area hit hardest by the blaze to temporarily return home. El Paso County sheriff Terry Maketa said Monday that local, state and federal investigators are "zeroing in on the point of origin" of the Black Forest Fire near Colorado Springs. He said were working to bring in some heavy equipment to help that work. Nearly 500 homes have been lost in the 22-square-mile fire, which is 75 percent contained. Two unidentified people who were trying to flee were found dead in the rubble. There were no lightning strikes when the fire broke out Tuesday amid record breaking heat so it's believed the fire must have been caused by a person or a machine. Wildfires were also burning in other parts of Colorado as well as California and New Mexico. A wind-whipped wildfire near the main route into Yosemite National Park in the Central Sierra foothills forced the evacuation of about 150 houses and threatened others, California Department of Forestry and Fire Protection spokesman Daniel Berlant said Monday. In New Mexico, crews have contained the majority of the 94 square miles of wildfires raging throughout the state. The largest fire, the 37-square-mile Thompson Ridge Fire, was 80 percent contained. Near Colorado Springs, the fire investigation is one reason authorities have been hesitant to let people back into the most developed area where there was concentrated devastation from the fire. They want to preserve evidence in what could be turn out to be a crime scene. Firefighters are also working to make sure the interior of the burn area is safe, by putting out hot spots and removing trees in danger of falling. Maketa said residents could be temporarily allowed back on Tuesday or Wednesday. He said he understood that some people might want to go back for just a short time as part of their grieving process while others might want to stay for several hours and start cleaning up. He promised authorities would work with whatever their needs were. "We're not ignoring you and we're with you," Maketa said. Residents have been anxious to return and some who were escorted back for emergency situations have refused to leave again. Firefighters could get some help from more rain Monday. A steady rain fell Sunday but they also had to scramble to put out three small fires sparked by lightning from the storm. Her daughter, Jordan Dawson, 25, who was on her way from Denver to visit, spotted the smoke, called her mother and went to the house. The fire only a few miles away from the state's second-most destructive wildfire, the Waldo Canyon Fire, which started nearly a year ago. The cause of that fire still hasn't been determined. The memory of that fire might have made residents especially appreciative of firefighters. Large crowds have been turning out to line the road and cheer crews as they return from the lines. Incident commander Rich Harvey said that support has helped firefighters get through methodical but not very exciting mop up work needed to get residents back to their homes. "When it gets down to the grind, it's hard to stay motivated," he said. In Canon City, 50 miles to the southwest, a wildfire that destroyed 48 buildings at the Royal Gorge Bridge & Park is fully contained. A lightning-sparked fire in Rocky Mountain National Park has burned about 600 acres and was 75 percent contained. In western Colorado, a 500-acre wildfire burning north of Rifle is 60 percent contained. It was started Friday by a smoldering lightning strike.