MORGANTON, N.C. — A full-scale search was under way Thursday at the Burke County, N.C., property where investigators have visited three times earlier this week, seeking clues in the disappearance of 10-year-old Zahra Baker.

Authorities also are reported to be planning a search of the Caldwell County residence where Zahra and her parents — father Adam and her stepmother Elisa — lived before moving to Hickory, N.C., about six or seven weeks ago.

Meanwhile, there were published and broadcast reports Thursday that police are convinced Zahra made the move to Hickory with her parents during the summer and was seen as recently as mid-September.

And the Hickory police on Thursday afternoon asked media outlets in the region for any video interviews of family members.

The Burke County Sheriff’s Office sent about 50 searchers to the property north of Morganton that is owned by the company Adam Baker is employed by. Crews searched the same site twice Tuesday and then drained a 4-foot-deep pond near the property Wednesday night. They apparently did not find any clues in the disappearance of the girl.

Burke County authorities said Thursday’s search will be thorough — piece by piece, in a grid format — so they can either find answers or eliminate the site, once and for all. Search dogs also are poring over the property.

According to WSOC-TV, police plan to be in Caldwell County later Thursday to conduct another search of at least one residence where Adam and Elisa Baker lived with Zahra. The Bakers had multiple residences in Caldwell County before moving to Hickory, from where Zahra was reported missing Saturday by her father.

WSOC-TV said it was told by police investigators they have confirmed that Zahra was still alive when her family moved to Hickory. Earlier this week, Hickory police said they were having trouble finding people who had seen Zahra “”recently.”” But police told WSOC that they are convinced the girl was alive about a month ago.

Several hundred people gathered Wednesday night at a Hickory church for a candlelight vigil for Zahra, at the same time as police expanded their search for the missing girl and drained a pond near the tree-trimming company where her father has worked.

The search at the Burke County pond ended before midnight, and investigators said they did not find anything to help in the case. The pond was near the same property where searchers looked Tuesday.

Searchers used hoses to drain the pond, which is about 4 feet deep, but found nothing.

“”It’s very disappointing,”” Burke County Sheriff’s Office Lieutenant Becky Weatherman told reporters. “”If she’s deceased, we would like to provide closure for the family.””

Early Wednesday, Zahra’s stepmother Elisa Baker made her first appearance in court on obstruction-of-justice charges after investigators said she admitted she wrote a phony ransom note found at the family’s home on Saturday.

Police say the note was designed to throw off investigators in their search for answers in the girl’s disappearance, a case they’re now calling a homicide.

At Wednesday evening’s vigil, people sang and prayed for Zahra outside East Hickory Baptist Church, their children playing on swings and a jungle gym nearby.

“”We just want to lift up little Zahra as we think about the tragedies in her life,”” deacon David King told the crowd.

At the vigil, Lindsey Parker told the crowd that family members had reported suspected abuse of Zahra to the Department of Social Services on three occasions. She said she was speaking on behalf of Brittany Starbuck, one of Elisa Baker’s three children from a previous marriage.

“”DSS was called three times,”” Parker said of the family. “”They tried. They really tried.””

DSS officials in Caldwell County, where the family recently lived, have not responded to requests for information.