Authorities will scale back the hunt for missing Florida girl Haleigh Cummings after extensive searches for the girl turned up no new leads, The Gainesville Sun reported Monday.

Despite tips and a search involving 250 volunteers — including Texas EquuSearch, a volunteer search group — investigators are baffled about the whereabouts of the 5-year-old.

"This is frustrating," Chief Deputy Rick Ryan of the Putnam County Sheriff's Department said in a Sunday news conference. "This is not 'CSI.' We can't wrap this up in an hour."

Click here for photos.

Ryan told The Sun that the sheriff's office will search two more smaller areas on Monday before ending the ground search.

Investigators continue to interview family members, their friends and others. Everyone is considered a potential person of interest.

"The family has been extremely cooperative and happy with our efforts," Chief Deputy Ryan said Saturday.

Haleigh was discovered missing from her home Tuesday morning by her father's girlfriend, Misty Croslin. The father, Ronald Cummings, said Haleigh had gotten up to use the bathroom, and when she didn't return, Croslin went to look for her and noticed the back door of the mobile home they shared was open.

Police haven't narrowed down a list of suspects in the case, and they have received more than 350 leads.

"All the sex offenders [in the area] have been interviewed and their residences have been searched," Putnam County Sheriff Jeff Hardy said earlier. "They're cleared as far as us contacting them and speaking to them."

Cummings and Croslin told FOX News' Greta Van Susteren last week that they both had submitted to polygraphs and "passed" the tests. Sheriff's officials would not release the results.

Croslin has told different stories to police and the media about what happened, according to MyFOXOrlando.com.

Police had never been called to the home in the past, but there have been investigations by a social services agency involving Cummings, Croslin and Haleigh and her 4-year-old brother Junior, according to Putnam County Capt. Steve Rose. He wouldn't elaborate.

John Harrell, spokesman for the northeast region of the Florida Department of Children and Families, said Thursday that his agency "was involved with the family." He wouldn't offer any details, citing state confidentiality laws.

In addition to Croslin and Cummings, the child's mother, Crystal Sheffield, has been questioned in the case.

Click here for more on this story from MyFOXOrlando.com.

Click here for more on this story from MyFOXTampaBay.com.

Click here for more on this story from The Gainesville Sun.