HAMILTON -- Family members of Tim Bosma winced and looked away as a police officer told his murder trial the details of a bullet casing and blood she found inside the Hamilton man's pickup truck.

Det. Const. Laura McLellan of Halton Regional Police testified Thursday that she and her team of officers didn't initially see the shell casing because it was lodged somewhere behind the truck's rear seat.

McLellan said it became dislodged as she snapped hundreds of photographs of the truck and the trailer it was found in -- a trailer that was registered to Millardair, an aviation company owned by Dellen Millard -- one of the two accused.

Millard, 30, of Toronto, and Mark Smich, 28, from Oakville, Ont., have pleaded not guilty to first-degree murder in Bosma's death.

Bosma disappeared on the night of May 6, 2013 after taking two strangers on a test drive of a black Dodge Ram pickup truck he was trying to sell. His charred remains were found more than a week later.

McLellan told court she began examining the truck on May 15, 2013, alongside blood spatter specialists from Waterloo Regional Police and scientists from the Centre of Forensic Sciences.

The bullet casing was a bit of a surprise, since earlier photos, which were shown to court, didn't show it.

"Clearly it fell during our photo examination," McLellan said as a magnified photograph of the brass shell casing with the markings "WIN 380 AUTO" flashed on television screens in the Hamilton courthouse.

At that point, Millard looked over at Smich, who was seated next to him, and shook his head. Smich didn't return the look.

"That is a simple piece of brass," McLellan continued, explaining the shell casing to the jury. "It's already been fired, the bullet has been ejected."

After finding the shell, she swabbed the truck for gunshot residue and sent the sample for further analysis.

McLellan told court she found blood throughout Bosma's truck, both inside and out. She sent 64 swabs of blood from the truck and contents of the trailer it was found in for forensic analysis.

She said blood was found on the front passenger side, on the dash, in the cracks of the truck's vinyl and on the ceiling above the driver's side.

McLellan said she didn't even need the orange goggles that she usually uses with a special laser to see the dark stains that field tests indicated were blood.

There also was blood on a tarp found in the bed of the pickup truck, blood on the undercarriage, and blood on the muffler.

The front passenger window was shattered. The front seats and carpets were ripped out, and the charred remains of the seats were found in the back of the trailer. They also found a box cutter on the truck's floor.

There were three green tarps in the bed of truck along with the vehicle's headlights, taillights and its identifying emblems. She said they detected blood on two parts of one of the tarps.

Earlier Thursday, Phil Wilkinson, a cellphone expert with the Ontario Provincial Police, described the movements of phones registered to Millard and Smich in the hours and days following Bosma's disappearance.

Shortly after midnight on May 7, Wilkinson said Millard's phone pinged off cell towers near Millardair, the company owned by Millard and operated out of a hangar at the Region of Waterloo International Airport.

Crown Attorney Craig Fraser methodically laid out maps made by Wilkinson that showed the movements of the phones, which seemingly travelled together often as they sent and received texts and phone calls.

The maps showed cellphone activity pinging off towers near Millardair, Millard's farm in nearby Ayr, Ont., near places Smich stayed in Oakville, Millard's home in Toronto and Millard's mother's house in Kleinburg, Ont., where Bosma's truck was eventually found.

On Wednesday, court heard the phones registered to Millard and Smich -- and a third phone registered to Lucas Bate, which police believe is a bogus name -- travelled together from Toronto to Oakville to Hamilton and arrived near Bosma's home around 9 p.m. on May 6.

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

The case will resume on Tuesday.