By Marisa Gerber
TUCSON, Arizona (Reuters) - The search for a missing 6-year-old Arizona girl who authorities say may have been snatched from her bedroom in Tucson entered its third day on Monday as search dogs shifted investigators' attention back to the child's home.
The parents of first-grader Isabel Mercedes Celis told detectives she was last seen on Friday night when they tucked her into bed, and was found to have vanished when a family member entered her room the next morning to awaken her, police said.
After an intense but fruitless door-to-door search of a 6-mile-wide swath of Tucson surrounding the girl's house over the past two days, investigators were focusing on Monday on the interior of the home itself, Tucson Police Chief Roberto Villasenor said.
Two specially trained dogs brought in by the FBI arrived on the scene late on Sunday, he told a news conference on Monday morning, and "the dogs did alert on a few things ... but what exactly that is we're trying to determine."
"We have information obtained from the dogs that necessitate our follow-up investigation," the chief said. "In order to do that, we secured the residence, we've asked the family to leave the residence, so we don't have to talk about any other contamination of the scene. And we will conduct that follow-up investigation."
Police have said they are treating Isabel's disappearance as a "possible abduction" and that they are not ruling anything in or out and have not identified any suspects in the case. Villasenor said the family has been cooperating with investigators.
Isabel lives at the house with her mother, father and two older brothers, police said. They will be permitted to return to their home "once we are satisfied that we have completed all the investigation that needs to be done in the house," Villasenor told reporters.
The chief also confirmed reports that a window to the bedroom was found open and that a screen from that window had been removed, but he stopped short of saying that an intruder was believed to have entered the house that way.
"That would be a potential point of entry that we've been interested in from the beginning," he said.
Police have said the child had no history of wandering off or running away from home.
After cordoning off the immediate vicinity of the house, search teams made several passes through an area stretching 3 miles in all directions from the family's home, police said.
Police Lieutenant Fabian Pacheco said investigators had questioned all 17 registered sex offenders in that area, a middle-class neighborhood consisting mainly of single-family dwellings, but those interviews turned up no clues.
Investigators also were canvassing residents and local merchants and handing out fliers with Isabel's photo and looking for any video from surveillance cameras that might have captured something. Villasenor said police have received more than 100 leads in the case.
(Additional reporting by David Schwartz; writing by Steve Gorman; editing by Mohammad Zargham)