The evidence from a "bloodletting event" inside Tim Bosma's truck all points to someone being shot while in the passenger seat of the truck, a blood spatter expert told a Hamilton court Monday.

Testifying at the trial of the two men accused of killing the Hamilton man, Sgt. Robert Jones of Waterloo police told the jury that blood spatter found on the inside dash of Bosma's truck came from the passenger side area.

Previously, the jury heard that Bosma disappeared in May 2013 after leaving his home with two men who wanted to test drive a truck he was selling. He was sitting in the passenger seat of his truck when the three left.

"The source has to be a little towards the right side or the passenger side," Jones said.

The jury previously heard there was a one in 18 quadrillion chance that the blood on Bosma's truck came from anyone other than the slain man.

Dellen Millard, 30, of Toronto, and Mark Smich, 28, of Oakville, Ont., are accused of killing Bosma, 32, who lived in the suburban Ancaster area of Hamilton. Both men have pleaded not guilty to first-degree murder in Ontario Superior Court.

Efforts made to clean up truck

Monday's testimony was dominated by the blood spatter evidence in the truck, and once again, the contentious location of a spent .380-calibre shell casing found inside the truck.

Jones told the jury Monday that many of the stains on the inside and outside of the truck appeared to be "altered," possibly the result of trying to clean them up with a hose or pressure washer.

He testified that there was almost certainly an attempt to clean up heavy, smudged bloodstains found on the dash near a power outlet.

"It was probably the only area where I could [concretely] see there was cleanup, and it appeared there was an area of more blood," Jones said.

"When you're cleaning up blood, it's not as easy as it might look. Once the blood dries ... it takes some effort to get it off."

Bloodstains were also found in the dashboard cupholders, in the back seats and on the truck's exterior and its undercarriage.

Many of the stains were consistent with a hose or power washer being used, Jones said.

Parts of truck stripped

Bosma truck blood

Sgt. Robert Jones testified that these bloodstains on the front passenger door appeared to be consistent with smudges from someone's fingers when closing the door. No ridges could be seen for fingerprints, he said. (Court exhibit)

Much of the truck's interior had been stripped when it was located by police, court has heard. The front seats were pulled out, along with carpeting. A charred front seat assembly was found inside the trailer where Bosma's truck was found.

"Five splatter bloodstains inside the vehicle indicate that a bloodletting event happened inside the vehicle. I'm missing too much inside the vehicle to say how big the event was," Jones said.

"I'm suspecting that there was information that might have helped me out, and that's why they're missing," Jones said.

In cross-examination, Millard's lawyer Ravin Pillay said that Jones couldn't concretely say what caused the blood to spatter where it did in the truck.

"There are many ways blood can be impacted to cause spatter stains. It could be somebody striking an area where there's blood, it could be somebody used an object to strike an area where blood is then dispersed, it could be a person falls and causes blood to be dispersed," Pillay said. Jones agreed that was possible.

"You agree with me that blood can spatter from trying to move a body that has been bleeding?" Pillay asked.

"It's possible," Jones said.

Lawyers wrangle over shell casing again

Once again, the defence lawyers argued over the location of a shell casing found inside the truck. Smich's lawyer Thomas Dungey took Jones to task for not writing down anything about the shell in his notebook at the time of the initial examination.

"We've got a casing here and you're the stain guy, and you're telling us you're not going to note it in your book?" Dungey said.

"The casing tells me nothing about blood analysis," Jones said.

The .380-calibre shell casing was found near the back seats of the truck. Dungey asked Jones if it would be possible for the shell casing to end up there if the driver shot Bosma, and the shell ejected into the back seat.

Tim Bosma

Tim Bosma disappeared in May 2013. The trial of two men accused of first-degree murder in connection with his death continues in a Hamilton court this week. (Facebook)

"Would you not agree with me officer, that if you take into consideration that the driver shoots Mr. Bosma and the window is smashed due to the shot, that could go into the theory that the shooter was the driver?" Pillay asked.

"I would need bloodstains to back that up," Jones said.

Pillay objected to most of that line of questioning, as Jones had not been qualified by the court as a reconstruction expert.

Chemical sprays called leucomalichite green and luminol were used to test areas on the truck for blood, court heard. The chemicals react with the hemoglobin in human blood to reveal blood that can't be seen with the naked eye. One makes blood turn green, while the other makes blood glow in low light.

Court was shown a photo of the truck's bed after it had been treated with luminol. It was glowing all over.

CBC reporter Adam Carter is in the courtroom each day reporting live on the trial. You can view a recap of his live blog here:

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