LEE COUNTY, N.C. — Investigators are expanding their search for a missing Lee County woman. On Thursday, authorities used cadaver dogs to search an area lake for signs of Julie Bullard.

Lee County authorities said that more than a dozen people are searching a four-county area for clues to Bullard's whereabouts after an alleged home invasion and kidnapping early Monday morning. They also said that some people have been working 18-20 hour days in their quest to find Bullard.

Officials said that there have been two new tips phoned into authorities after a public plea Wednesday by Bullard's mother. Both were of alleged sightings of Bullard in the area. However, authorities say that neither tip panned out.

On Thursday, investigators went back to a pond near the home where a masked man allegedly abducted Bullard during a social gathering early Monday morning. The area around the pond had previously searched the area around the pond for clues. On Thursday, a boat and the cadaver dogs were used in the pond, and the water was dragged for evidence.

Authorities say that the pond was re-searched to make sure that there was no evidence being overlooked by investigators. However, nothing was found during Thursday's search.

Anyone with information relating to Bullard's disappearance is asked to contact local law enforcement agencies immediately.