Police from Durham Region continue to search the Whitby, Ont. area Saturday afternoon for any signs of Jeffrey Boucher.
The 52-year-old high school teacher has been missing since Monday, after he is thought to have gone for a jog.
Insp. Nick Lisi says despite the lack of new evidence, the search continues on this sixth day in and around Boucher's neighbourhood.
Police today are focusing on a wooded area marked by gullies and ravines near Boucher's home. An aircraft is standing by if needed.
"I think we still have to focus on ground zero here, in that respect. We would be remiss as a police service if we weren't sure we've gone through this whole area," Lisi told CBC News. "This a very complex geographical area."
The ground search was recently scaled back, but is expected to continue into next week.
It's thought Boucher, an avid runner known for going on long runs almost daily, went for a jog early Monday, though according to police no one saw him leave.
Extensive ground and air searches have covered most of the areas where Boucher was known to go running.
Experts say it's unlikely he would be able to survive outside in the cold for more than 24 hours if dressed only in running gear.
Police have not ruled out the possibility that the husband and father of two may have simply walked away from his life, but have also found no evidence such as banking activity or border crossings.