ORO-MEDONTE, Ont. - Rain, mud and chilly weather have not deterred some 400 people from joining the ground search for missing Ontario boy Brandon Crisp.
  
The volunteers embarked Saturday on a second day of searching for the 15-year-old from Barrie, Ont., as software giant Microsoft doubled the reward money for information on his whereabouts to $50,000.

Public search organizer Charmaine Nolan, who works with Brandon's mother, said school bus loads of volunteers are scouring dense bush area and fields.

Barrie police, who are on day seven of their own search just southwest of the civilians, say no meaningful clues have turned up yet.

Sgt. Dave Goodbrand says people from Miami to British Columbia have offered assistance, including search and rescue expert Terry Grant, host of Canadian reality show "Mantracker," who flew in to help.

The teen ran away from home Oct. 13 after fighting with his parents about his Microsoft Xbox game system, which they say he is addicted to.

Anyone with information should call Barrie Police at (705) 725-7025.

People can help out with the search by calling Charmaine Nolan at 705-721-3576. Volunteers will be searching from 9 a.m. to 6 p.m. Friday, Saturday and Sunday.