Authorities are asking residents on Maryland's Eastern Shore to search their own property for signs of a missing girl as thousands of volunteers fanned out but found no sign of her.

Police believe 11-year-old Sarah H. Foxwell was abducted by a registered sex offender.

Thousands of volunteers gathered in Salisbury on Friday morning to help in the search. State police from nearby Delaware are also assisting.

Thirty-year-old Thomas J. Leggs Jr. has been charged with kidnapping Sarah. Leggs, a registered sex offender, is a former boyfriend of the girl's aunt, who is her legal guardian.

SLIDESHOW: Police Search for Missing Girl in Maryland

Wicomico County Sheriff Mike Lewis said Sarah was last seen Tuesday night at her home on Maryland's Eastern Shore. A relative discovered she was missing early Wednesday while checking on Sarah and her 6-year-old sister.

"She wasn't in her room," Lewis said. He said there was no evidence of forced entry to the home where the girls live with their aunt, who is their legal guardian.

Dive teams searched a local pond Wednesday night, and scores of police officers from across the region scoured several square miles of dense woods on Christmas Eve. They brought in helicopters and dogs to aid their search.

Police also released a photograph of a 2003 Dodge Ram 1500 pickup used by Leggs and they asked anyone who may have seen the champagne/tan-colored vehicle to contact authorities.

Sarah is white, 4-foot-8 and weighs 78 pounds. She has brown hair and blue eyes. When she disappeared, she was wearing red fuzzy pajama bottoms with Christmas trees on them and a pink John Deere T-shirt.

"I will tell you this: We have not given up hope and we will continue to search all day today and throughout the night," Lewis said Thursday. "We won't go home until we find this little girl."

Leggs is being held at the Wicomico County Detention Center without bail, Lewis said. He is being represented by the public defender's office, which did not immediately return a call seeking comment.

Lewis said Leggs has been convicted of sex offense in Wicomico County and was charged Oct. 29 with fourth-degree burglary.

"He was developed as a suspect early on in the investigation before we were aware of his criminal background, but he does have a criminal history to include third- and fourth-degree sex offenses of small young females," Lewis said.

In 2001, Leggs was convicted in Delaware of rape for having sex with a victim who was 16 or 17, according to the Delaware registry. The registry describes his risk level as "high" and notes he is unemployed.

Leggs, who has been convicted of assault several times, also is awaiting trial on charges of burglary and destruction of property in Ocean City.