The search for missing Maine teen Jaden Dremsa turned on Monday to Lake Arrowhead as the state Warden Service continues its efforts to find the boy who has Asperger’s syndrome, a form of autism.

"A lot of search and rescue is math and we are getting the statistics from our manual," Lt. Kevin Adam, of the Maine Warden Service told NBC-affiliate WCSH, in Portland.

"Based on the information, you draw a circle and when you do that, it says 75 percent of the time you should find the person in that radius, but we haven't. That's why it's frustrating -- we want to find Jaden and bring him back to his family. Sometimes, I feel like we aren't getting closer to that.”

The wardens said that they still hope to find Jaden alive but are exploring all possibilities. On Sunday, Lake Arrowhead was drained by about three feet so it would be easier for rescuers to reach the bottom. The lake in North Waterboro is the focus of the search because someone said they saw a boy matching Jaden’s description near the lake, but a rescue dog wasn’t able to link the 15-year-old Waterboro teen's scent to the body of water, according to WCSH. Divers won’t be sent in to search the lake unless searchers find evidence that Jaden’s body is there, New England Cable News reported.

"It's just a theory right now," Adam said. "Anytime we ever search near water, we have to look at it."

The search for Jaden has spanned a 10-mile radius, including foreclosed homes and other places where authorities believe he might have sought shelter, officials told Portland ABC-affiliate WMTW.

“It’s frustrating for us, frustrating for the searchers, frustrating for the family," Adam told the Bangor Daily News. "We’re all looking for clues just not a lot that lead anywhere.”

Jaden went missing from the Twin Pines Trailer Park in North Waterboro around 3 p.m. Thursday. He was described as 5-foot-9-inches tall and about 140 pounds. He was last believed to be wearing a dark T-shirt, blue jeans and sneakers.

Autism