Travis Vader frequently stole trucks and made a habit of burning them afterwards, according to a star Crown witness who testified under heavy security Thursday in an Edmonton courtroom.

Dave Olsen walked into the courtroom flanked by sheriffs and RCMP officers. He appeared to be nervous and wore an ill-fitting suit.

Throughout his testimony, two sheriffs stood at attention behind the witness box.

Travis Vader is on trial for first-degree murder in the deaths of an elderly St. Albert couple. (CBC) Court has been told that Olsen is under RCMP protection and was brought to Edmonton from an undisclosed location, and will return there once his testimony has concluded.

It was also revealed Olsen entered into an agreement with the RCMP as part of a witness protection program.

He testified the Mounties spent approximately $24,000 to relocate him, get him furniture, pay his first three months rent and provide food and transportation.

"From that point on, I paid everything," he said. "Very little of that money was given to me directly."

Olsen told the court he met Vader in 2009 through a family member, and for a time they were together almost every day.

He said they spent their time, "doing a lot of drug smoking, like meth. Drinking beer. Boxer Beer. Lucky. Pilsner Brew House. Whatever was cheapest, normally."

In 2010, Vader "was living all over the place" and didn't have a job, Olsen testified. He said he saw Vader's final paycheque for "around $100,000" and said that "three months later, it was all gone."

According to Olsen, Vader had a truck that developed transmission problems, then was eventually repossessed.

"How did he get around after that?" asked Crown prosecutor Ashley Finlayson

"Stolen rides, mostly," Olsen answered. "I've seen him in as many as 25 to 30 different trucks. A lot of times he told me they were stolen. He even told me how he'd burn them."

Vader is on trial for first-degree murder in the deaths of Lyle and Marie McCann, who were last seen on July 3, 2010.

Court has been told about a stolen white pickup truck that was found burned, with the keys to the McCanns' Hyundai SUV tucked into the truck bed.

Olsen told the prosecutor around 10:30 a.m. on July 3, Vader visited him in the town of Peers, driving a truck that looked like the stolen white pickup.

In cross-examination, he admitted Vader could have arrived the first time much later in the day, possibly at 2 or 3 p.m.

The time frame could end up being crucial to Vader's case. The Crown alleges Vader used the McCann's cell phone to send text messages to his ex-girlfriend at 2:28 and 2:32 p.m.

'He told me he was broke'

"It was basically a quick stop," Olsen said. "He didn't stay long. He told me he was broke. He didn't even have money to buy his own oil for the truck. I had to give him my lawnmower oil."

Vader returned to Olsen's mobile home around 5 p.m. that day, this time driving a different vehicle. Olsen said Vader backed a light-green Hyundai SUV into Olsen's driveway, close to the front steps, then came inside the trailer.

Olsen described the SUV as "clean. Really clean. It looked like new."

By then, Vader had money.

"He took a small roll of bills out of his pocket," Olsen said. "I can't say for sure how much he had. And he sent me to the store with 50 bucks."

Vader had money left over, and wanted Olsen to buy him beer and a $25 mobile phone card.

Olsen said he bought the phone card and a case of Boxer beer. Earlier evidence entered at the trial reveals the phone card was purchased at 5:29 p.m. and the beer was bought at 5:35 p.m.

The Boxer brand has featured prominently in the trial. Police later found a can with Vader's fingerprints and DNA in the front console of the McCanns' SUV.

The two men sat outside and drank beer. Olsen said Vader seemed "agitated, upset about something. I can't say. He mentioned Amber a lot."

Amber Williams was Vader's ex-girlfriend. Olsen said Vader wanted to buy the cellphone minutes in order to reach her.

After visiting for "an hour or two," Olsen said Vader drove off in the SUV.

"And that was the last time I seen that car," he said. In cross-examination, Olsen said Vader might have left as late as 7:30 p.m.

Ten days later, Olsen spotted a front page newspaper story about the missing St. Albert couple that referred to their burned-out motorhome and missing light-green Hyundai SUV.

By chance, RCMP stopped by Olsen's mobile home to make sure he was abiding by bail conditions. Olsen told them about seeing Vader in the SUV on the same day the McCanns disappeared.

At the end of a very long day on the witness stand, the prosecutor asked Olsen why he came forward to the RCMP, and why he chose to testify.

"Because it was the right thing to do," he said. "That could have been anybody's grandparents."

The Crown revealed it expects to wrap up its case by the end of next week. The defence plans to begin its case on May 9th.