HAMILTON -- One of the lead investigators into the death of a man slain after going on a test drive with two strangers told jurors on Wednesday that it was a tip about one of the accused killer's tattoos that gave police a major breakthrough in the case.

Det. Greg Jackson said a Toronto man, Igor Tumemenko -- scheduled to testify later in the trial -- told police about a test drive linked to the same phone number involved in Tim Bosma's disappearance. Bosma's body was found a week later burned beyond recognition.

Jackson told jurors that Tumemenko was also contacted via the same Toronto-area cellphone used to call Bosma on the night of May 6, 2013, when he left home for a test drive and never returned.

Tumemenko, who went on the test drive a day before Bosma's disappearance, told police about a tattoo of the word "ambition" on the wrist of one of the men as they drove his Dodge Ram truck.

Dellen Millard, of Toronto, and Mark Smich, from Oakville, Ont., have both pleaded not guilty to first-degree murder in Bosma's death. Millard has a tattoo with the word "ambition" on his left wrist.

The Crown alleges Bosma was shot inside his truck and later his body was burned in an incinerator.

After hearing from Tumemenko, police focused their investigation on the tattoo and the cell phone, Jackson said.

"In the course of the investigation, you received information from two reliable police sources in Peel and Toronto about Mr. Millard having an ambition tattoo, correct?" asked Crown attorney Anthony Leitch.

"That's correct," Jackson said.

Jackson said they tried but were unable to get finger and footprints from Tumemenko's truck.

Investigators then received Millard's cellphone records and cell tower locations that showed a call from his phone to a number in Ancaster, a rural region of Hamilton, at 9:02 p.m. on the day Bosma disappeared, Jackson said.

Bosma's widow, Sharlene, and their tenant, Wayne De Boer, have testified that Bosma went on a test drive with two men sometime after 9 p.m. from his home in Ancaster.

Jackson said Millard's phone then pinged off a cell tower in Brantford, Ont., at 9:44 p.m., before pinging twice around midnight in Cambridge, Ont. The last blip from Bosma's phone, on the other hand, was off a tower in Brantford at 10:56 p.m.

Police traced the calls made to Bosma and Tumemenko to a cellphone number belonging to a shop in west-end Toronto, Jackson said. The name on the bill of sale was Lucas Bate.

Cell tower records showed similar locations for the two phones -- Millard's and Bate's -- travelling from Etobicoke, in west-end Toronto, through Ancaster, Jackson testified.

The investigator also described the phone interactions between Bosma's cellphone and Bate's. There were several calls between them, with Bate calling Bosma at 9:04 p.m. on the night he disappeared, Jackson said.

"At 10:01 p.m., Mr. Bosma's phone was used -- browser use -- and by 10:02 the phone was off," Jackson told court.

Police were unable to find anyone named Lucas Bate at the address on the cellphone receipt -- a high school in Etobicoke, Jackson testified.

Four days after Bosma disappeared, Jackson said two detectives visited Millard at an airport hangar in Waterloo, Ont. Millard is the owner of Millardair -- an aircraft maintenance and repair business, part of an aviation empire started by his grandfather 50 years ago.

Staff Sgt. Paul Hamilton was one of the detectives, and his testimony resulted in a surreal moment in court.

"Do you see the person you described as Mr. Millard?" Leitch asked Hamilton at one point.

"Yes, at the back table with the white shirt," Hamilton said.

Millard waved back.

Hamilton testified that when he arrived at the airport hangar, Millard "made a comment that the 'suits are here."'

The investigator told Millard police were looking into a missing person's case and a tip had led them to the hangar.

"He said, 'let's put a pause on this' and went back to his office, closed the door," Hamilton said.

One of his tasks, Hamilton said, was to help ascertain Millard's height as well to look for a satchel described by Tumemenko.

Millard put a canvas satchel over his shoulder, Hamilton said, and then he gave the detectives his phone number and the address of a farm he owned in Ayr, Ont., just outside the Waterloo region.

The two officers left the hangar and immediately called Waterloo Regional police to ask for help from their surveillance squad.

Later, court heard from a man who found Bosma's cell phone in Brantford, Ont., about 30 kilometres from Bosma's home, as he was mowing the lawn at a local business. He handed the phone over to a woman working there, Elizabeth Roswell.

Roswell testified that when the phone was plugged in, it started "pinging" as text after text "kept popping up." She called Bosma's home, and his sister told her to call 9-1-1.

In his opening statement, Crown attorney Craig Fraser said police found gunshot residue as well as Bosma's blood both inside and outside his truck.

Fraser said they have video of the incinerator being used outside Millard's airport hangar in the early morning hours after Bosma disappeared. The Crown said two of Bosma's bones, and many bone fragments, were later found in the incinerator.