TEWKSBURY, MA ?Officials still have not located a 40-year-old woman who was last seen at Tewksbury State Hospital on July 16. As the search for Heidi Burke, 40, entered its third week, Tewksbury Police Chief Timothy Sheehan said the most recent activity on her cellphone had been detected on Elm Street in Andover and North Andover, close to Merrimack College.

"Unfortunately, there is a 1.5-mile radius on the newest location track," Sheehan said. "We have notified all three police Departments ? Lawrence, North Andover and Andover ? and have forwarded all pertinent information regarding her status. They are currently all on watch for any sightings."

In the days following the initial report of her disappearance, police tracked her cellphone to Lawrence. Burke is white, 5 feet 4 inches and 180 pounds, with blue eyes and brown hair. Anyone with information about Burke is being asked to call Tewksbury police at (978) 851-7373.