When police Sgt. Annette Huys first came upon a livestock incinerator on a farm owned by Dellen Millard in Ayr, Ont., she worried that someone could be inside it.

She couldn't help but think so, Huys testified in Ontario Superior Court on Wednesday in Hamilton, just because of the sheer size of the apparatus, dubbed "The Eliminator."

It was May 2013, and the Hamilton police forensics officer was on the farm executing a search warrant, not long after Millard's arrest.

Millard, 30, of Toronto, is facing a first-degree murder charge alongside his co-accused, Mark Smich, 28, of Oakville, Ont., in connection with the slaying of Tim Bosma, 32, of Ancaster, Ont. Both men have pleaded not guilty in the trial by jury.

When Huys climbed to the main hatch and opened it, she found only bones and fragments. The largest was about 20 centimetres long.

Immediately, she wondered where the bone came from.

"Is it animal? Is it human? I didn't know."

2nd bone found

After that first discovery, a second bone was found, about half the size of the first.

The Crown says the bones belonged to Tim Bosma, who prosecutors say was burned in the incinerator after being shot and killed at close range inside the Dodge truck he had been trying to sell online.

Two burn sites were found not far from where the incinerator was discovered. Court heard Wednesday that three seatbelt buckles were found among the charred corn stalks, alongside other small debris. (Court exhibit)

​His burned remains were found more than a week later.

For hours on Wednesday, dozens of photos of the bones were flashed on screens in front of Bosma's family and friends.

They have been there each day, filling the first three rows of the courtroom. While none of the testimony has seemed easy for them to hear, Wednesday's graphic evidence appeared to hit them especially hard. Some members of the family held each other and wiped tears from their eyes.

It was one of the most emotional moments the courtroom has seen, and it came a day after the family heard graphic testimony about blood being found on the inside and outside of Bosma's truck when it was recovered by police.

A 'big, redneck smoker'

Police were led to the incinerator by Chaz Main, who told the court that he was riding his dirt bike on May 10, 2013, when he came upon what he thought was a "big, redneck smoker" in the middle of the tree line.

It struck him as so odd that he took pictures of the device.

"Because nobody would believe me that it was there, probably," he said.

"If you told someone there was this brand-new trailer and a big redneck smoker in the middle of the bush … I wouldn't believe it," Main testified.

Main said from the witness box that he knew about the Bosma investigation from media reports and a missing person poster at a gas station.

The day after he saw what he thought was a smoker, he was again out on his dirt bike when police officers stopped him.

"I saw a flash of a camera and a bunch of cops," he said. "I asked what the big commotion was."

Burn marks found on the ground

The officers were there with a search warrant, investigating Bosma's disappearance. The day before, Millard had been arrested and charged with forcible confinement and the theft of Bosma's truck. He had not yet been charged with first-degree murder.

Sgt. Ben Adams from Hamilton police took Main to a police car and asked him if he had seen any unusual activity in the area.

"I showed them the location of the Eliminator and the excavator … and the burn marks," Main said.

"I immediately became concerned," Adams testified Wednesday. "I thought the information he gave me was compelling."

Main told the court he had seen burn marks on the ground in a field near where the incinerator was found. He had never seen them before, he said, because he was usually travelling through the area at high speeds on his dirt bike.

Court saw pictures of the burn marks — two large, black, charred areas in a field. Huys said that three seatbelt buckles were found among the dark spots.

Excavator also found

In cross-examination, Millard's lawyer Nadir Sachak asked about the arrangement Main said he and a friend had to ride in the fields. Main had told the court that a farmer who owned parts of the fields let them ride there for a case of beer and a bottle of Crown Royal whiskey.

"During the hundreds of times you and Adam have been on the property, not once had someone said to get off the property?" Sachak asked. "No sir," Main responded.

Sachak also asked about the path near a tree line on the property where the incinerator was found. "No one has ever told you you can't walk on the pathway, the roadway where the incinerator was?" Sachak asked. "No sir," Main responded.

The excavator that was found in a nearby swamp, Main said, had been there since winter.

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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adam.carter@cbc.ca