Police search for missing 6-year-old Ariz. girl

This undated photo provided by the Tucson Police Dept. shows Isabel Mercedes Celis. Tucson police are searching for a 6-year-old girl who went missing from her home on the city's east side. Isabel Mercedes Celis was last seen late Friday and discovered to be missing at about 8 a.m. Saturday, April 21, 2012.
AP Photo/Tucson Police Dept.

(AP) TUCSON, Ariz. - The overnight disappearance of a 6-year-old Arizona girl triggered a massive search Saturday by scores of police, FBI agents and a large contingent of deputy U.S. Marshals as officials investigated the possibility that she might have been kidnapped or just wandered off.

First-grader Isabel Mercedes Celis's parents last saw her in bed at 11 p.m. Friday, and they discovered her missing at about 8 a.m. Saturday, said Tucson police spokeswoman Sgt. Maria Hawke.

Police continued to search an area of Tucson around East Broadway Boulevard and Craycroft Road late into the afternoon using street patrols, canines, detectives and a helicopter.

Hawke said investigators were looking into all potential scenarios, including the possibility that Isabel got up and wandered out of the home she shares with her parents and two brothers or that she was kidnapped.

Investigators also were examining every door and window of the house for signs of a break-in, Hawke said.

Both parents live in the home, so police had no indication a child custody dispute was involved but weren't completely ruling it out.

The working-class neighborhood of single-family homes is sandwiched between a large shopping mall to the east and businesses and Catholic school to the west.

"Because of the possibly existing that this child could have been abducted, we're treating it as if it's that significant," Hawke said Saturday afternoon. "We don't want to be caught behind the ball by not exploring that possibility."

Hawke says at least 75 law enforcement officers were involved, possibly as many as 100, as more resources continue to arrive to help in the search and investigate the disappearance.

Isabel is described as just under 4-feet-tall and weighing 44 pounds, with brown hair and hazel eyes.