Updated

Putnam County investigators say they don't think that Misty Croslin-Cummings has been straight with them as they continue to investigate the disappearance six months ago of Haleigh Cummings from her father's home in Satsuma.

In a news release marking the child's sixth birthday Monday, investigators said the child's biological parents, Ronald Cummings and Crystal Sheffield, were not suspects.

But for the first time, they don't think Haleigh was abducted by a stranger. They said, Misty Croslin, who was baby-sitting the girl when she vanished from her father's mobile home in February, "continues to hold important answers in the case."

"She has failed to provide any sort of detailed accounting of the hours during the late evening and early morning of Haleigh's disappearance. Furthermore, physical evidence at the scene contradicts Misty's sketchy account of her evening activities."

Croslin married Cummings about a month after Haleigh's disappearance. Their telephone in Welaka has been disconnected and it is not known if Croslin has an attorney.

According to the news release, investigators have received more than 4,000 leads, all of which have been followed up.

They have conducted 138 formal interviews and several hundred informal ones. DNA samples were collected from many of those interviewed.

The Florida Department of Law Enforcement processed the crime scene and did analysis on DNA and fingerprint evidence, none of which has identified a suspect.

Thousands of acres have been searched by air, on foot and by horseback. Divers have combed the water areas near where Haleigh disappeared.

"Sheriff (Jeff) Hardy wants to assure the public, but mainly Haleigh's family, that we will continue to aggressively pursue this case," the news release said.

Also Monday, a Texas-based search group said it would conduct another search for Haleigh Cummings.

Tim Miller, director of Texas EquuSearch, said the 50 group members and volunteers would search in four to six weeks. He said he thinks weather and vegetation conditions will be more conducive to finding the girl.

Click here to read more on this story from MyFOXOrlando.com.