SUPERIOR, Colo.—A Colorado official says nearly 1,000 homes and other structures were destroyed, hundreds more were damaged, and three people are missing after a wildfire charred numerous neighborhoods in a suburban area at the base of the Rocky Mountains. Boulder County Sheriff Joe Pelle also said Saturday that investigators are still trying to find the cause of the wind-whipped blaze that erupted Thursday and blackened entire neighborhoods in the area located between Denver and Boulder. Pelle said utility officials found no downed power lines around where the fire broke out. He said authorities were pursuing a number of tips and had executed a search warrant at “one particular location.” He declined to give details. A sheriff’s official who declined to provide his name confirmed that one property was under investigation in Boulder County’s Marshall Mesa area, a region of open grassland about 2 miles west of the hard-hit town of …