CINCINNATI -- The search for a missing 3-year-old developmentally disabled boy near Cincinnati ended Saturday.

The Hamilton County Sheriff's Office is calling off the search for Marcus Fiesel until further notice, NewsChannel5 partner ONN reported.

Authorities will follow-up on any hard leads they get, and they are asking the public to call if they see any sign of Marcus.

Fiesel was last seen Tuesday afternoon in Juilfs Park in Anderson Township, before his foster mother, Liz Carroll, passed out, and was taken to the hospital.

Marcus' foster father, David Carroll, said he knows people are suspicious that he and his wife may have done something to Marcus. But he said that simply isn't true. He points out that people were asked if they had seen his wife in Juilfs Park on Tuesday, without knowing what Liz Carroll looks like. She has been hospitalized since Tuesday.

Images: Toddler Missing

On Friday, restaurant owner Jeff Ruby put up a $10,000 reward for information leading to the location of the boy or anyone responsible for his disappearance.

Authorities said they searched the foster parents' home on Thursday and probably would hit that and other sites that already have been searched again, even as they expand to new areas.

Dogs and helicopters were used in the search, and aerial photos, maps and charts dotted the walls of the temporary command center that had been set up at the park office.

The use of hundreds of volunteers who fanned out across Juilfs Park as the search began Tuesday has been curtailed as more experienced professional teams of searchers take over. Riemar said some of the expanded areas were so densely wooded that it was necessary to use more sophisticated equipment and techniques.

The park has showed signs of returning to normal as a few joggers, tennis players and mothers with children returned to the area that had reopened Thursday.

Authorities believe that Carroll, 30, of Union Township, was unconscious for about 10 minutes. When she came to, there were three toddlers nearby, but Carroll told people trying to help her that she had four children.

The other children, her 2-year-old son Bryce, 1-year-old foster child Bradley and Kelly, 1, a child Carroll was baby-sitting, were safe.

Carroll's husband, David Carroll, said Marcus has the mental ability of a child 12 to 18 months old. Marcus joined the family about four months ago and has a history of wandering off, he said. The child once left the home of his biological parents in the middle of the night and did the same thing while living with other foster parents.