Tim Bosma had taken two men for a test drive in his truck when he disappeared Monday night.
The pair had arrived at Bosma's Ancaster home just after 9 p.m., after arranging a test drive over the phone.
The 32-year-old had recently posted the pickup for sale on Kijiji and Autotrader and had listed his home number, police said.
On Wednesday, Hamilton Police homicide detectives announced they have taken over the investigation.
"If it's an unusual missing person, we are to be involved. This has unusual circumstances right at the onset, so we got involved…last night," Sgt. Matt Kavanagh said.
Bosma's wife saw the two men when they arrived at the house, police said.
The first is described as roughly 6 foot, one inch and 170-180 pounds. He had medium short brown hair. He was wearing blue jeans and a long-sleeved orange shirt with running shoes.
The second is around five foot, nine inches with a small to medium build. He had dark hair and had a red hooded sweatshirt pulled over his head. Both were white, and looked to be in their mid 20s.
Bosma had told his wife they were from Toronto, police said.
It's unclear how the men arrived at the home, though posts on social media suggest the two were dropped off by a third man in another vehicle.
"It is possible other people were involved, we know nothing about those people," Kavanagh said.
The truck – a 2007 black Dodge Ram 3500 pick-up truck with license plate number 726-7ZW – has been flagged at the border, and alerts have gone out to police forces across the region.
Police believe it was the truck, not Bosma, the suspects were after.
There has been no sign of the truck since Monday. Bosma had his cell phone with him, police said, but it has been turned off.
He was last seen wearing dark blue jeans, work boots, and a long-sleeved shirt.
Hundreds of well-wishers have posted messages of hope and encouragement on social media since news of his disappearance broke Tuesday.
Family and friends have delivered flyers across the GTA, and have organized searches of the Ancaster area.
The Spectator reached several people at the Bosma home in Ancaster Tuesday, but none would reveal their connection to the family or further details regarding his disappearance.
Anyone with information regarding Mr. Bosma's location is asked to contact Det. Greg Rodzoniak of the Homicide Unit at 905-546- 4863 or to call Crime Stoppers.