Police administered a lie detector test Sunday to the mother of two missing toddlers, the children's father told FOX News.

Authorities temporarily halted the search for a 2-year-old girl and her 3-year-old-brother while state investigators questioned their mother, Lottie Kain.

The kids' dad, Dennis Payne, told FOX News that he didn't believe his fiancée did anything to hurt the children.

Payne said Kain was in the bathroom when she heard something, and when she went out the kids, Jonah and Nicole Kain (search), were gone and the door was open.

Payne also begged anyone who took the children to please give them back.

The children were reported missing Saturday evening after last being seen at their Warren County (search) home, in east Georgia about 100 miles from Atlanta.

The search, which included police, a dog team and a helicopter, was "halted for the moment" Sunday afternoon while agents from the Georgia Bureau of Investigation (search) questioned the children's mother.

Georgia Bureau of Investigation agent Gary Nicholson told FOX News "the searchers have been searching almost 24 hours now" and their goal was to come back and start again on Monday morning.

Nicholson said police still have "an open mind in every aspect" as to what happened to the children. "We have brought some neighbors in to make detailed statements."

He said police "do not have any direct evidence" of a break-in. "The doors were not locked … it would not have been a case where someone needed to break in."

Temperatures dipped into the 30s Saturday night when the children were reported missing by their mother.

Kain told police that she couldn't find the children at about 6 p.m.

FOX News' Rita Cosby, Andrew Hard and The Associated Press contributed to this report.