The search for 15-year-old Brandon Crisp enters its third week after a world-renown tracker added his expertise to the search for the missing Barrie boy over the weekend

Terry Grant from the popular TV show Mantracker flew into Barrie to lend a hand to the search.

Grant says the weather isn't helping the search, but the search continues while investigators make theories about the boy's location.

"We can speculate all we want right now, but until we actually have a sighting, we're just going to speculate," says Grant.

Crisp has been missing since Thanksgiving, when he ran away from home following an argument with his parents who stopped him from playing Xbox. They claim he was addicted to a game.

Over a thousand volunteers and police combed areas around Barrie as they searched for clues over the weekend, but they have so far come up empty-handed.

Police are hoping Microsoft may be able to help in the investigation. The company, which makes the Xbox, broke privacy protocols and is poring through data on Brandon's gaming console to try and find clues that may help find the boy.

Several companies, including Microsoft, are collectively offering a $50,000 reward for information that leads to finding the missing boy.

The last sign of the boy was when investigators found his bike on a walking trail shortly after his disappearance. It had a flat tire.

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.