A cadaver dog with the Calgary Police Service indicated there were human remains in several areas on the property of accused triple murderer Douglas Garland days after a five-year-old boy and his grandparents disappeared.

Garland, 56, is charged with three counts of first-degree murder in the deaths of Nathan O'Brien, 5, Alvin Liknes, 66, and Kathy Liknes, 53. All three were last seen the night of June 29, 2014, when Nathan was sleeping over at his grandparents' home. Their bodies have not been found.

Cst. Darcy Williams testified Monday at Garland's trial that he was dispatched to Garland's farm on July 5, 2014, with Sully, a now-retired 10-year-old yellow Lab. The animal is trained to detect human remains.

Witnesses on Day 6 of the trial, which is into its second week, also included RCMP officers who were involved in the search of the farm near Airdrie, Alta.

The trial before Court of Queen's Bench Justice David Gates and a jury is scheduled to last five weeks.

Sully becomes 'frantic'

In four different areas, including near a wood chipper and a burn barrel, and at a pile of ashes, Sully gave his strongest sign that he'd found human remains — he sat down and waited for his handler.

In another area, the dog became "frantic," Williams testified.

"I noticed a really big difference in Sully's behaviour," said Williams. "I had never seen something like this from him before."

Two weeks later, on July 18, Sully returned to the farm with Sgt. Jend Lind and Cst. Aron Johnston. The dog showed "lots of interest" in a vegetable garden area on the property but never sat down, said Lind.

Sully is now retired. His replacement, Riggs, is being trained by K-9 unit officers.

Burn barrel 'actively burning'

RCMP officers were dispatched to the farm on July 4, 2014, around 5 p.m. to perform "a hostage rescue," according to Sgt. Troy Switzer, a tactical paramedic who was among other officers in an armoured vehicle as it drove onto the property with lights and sirens.

A large burn barrel was "actively burning" and "extremely hot," said Switzer, who was involved in searching the house and outbuildings for possible victims and "hostiles."

Nobody was ever found, but Switzer did notice a new-looking black duffel bag in one of the wooden outbuildings amid dirty, dusty clutter and boxes.

Inside were two pairs of handcuffs, an 8- to 10-inch hunting knife and a billy club.

The next morning, the burn barrel was still smouldering when RCMP Sgt. Timothy Walker arrived. Walker — who was the lead of the RCMP's forensic identification unit at the time — extinguished it with a garden hose.

Glasses, bone, tooth found in ashes

While the officer waited for the barrel and its contents to cool off, he and other officers used a chemical to test for blood in outbuildings on the property.

The test showed signs of blood in two different outbuildings, near light switches, but Walker confirmed under cross-examination the tests are presumptive and that false positives are a possibility. Swabs were taken and sent to a lab for further analysis.

Once the burn barrel contents had cooled, Walker sifted through and found pieces of what appeared to be electronic microchips, burnt paper and cloth.

The next day, Walker testified, officers began to sift through a dump pit of ashes found on the property just south of the burn barrel, and found a pair of glasses, bits of bone and what officers believed to be a tooth.

Empty, bloody home

Garland is connected to the Liknes family through his sister, Patti Garland, who was in a common-law relationship with Alvin Liknes's son, Allen.

Nathan's mother, Jennifer O'Brien, called 911 on the morning of June 30, after arriving at her parents' house to find it empty and smeared with blood.

After the Likneses and their grandson were reported missing, an Amber Alert was activated for the boy, but it was cancelled two weeks later after a massive search.

An aerial photo of the farm near Airdrie, Alta., where Douglas Garland lived with his parents. The prosecution told jurors on the first day of the trial that DNA from the missing family was found at the farm. (Court exhibit)

Garland was charged on July 15, 2014.

Patti Garland, her parents and Allen Liknes have all testified that Garland harboured a grudge against Alvin Liknes after a business relationship soured years earlier.

Tampered lock and DNA found

Kathy Liknes, grandson Nathan O'Brien, 5, and her husband Alvin Liknes were last seen on June 29, 2014. (Calgary Police Service)

Last week, prosecutor Vicki Faulkner said DNA evidence from the missing family members was found on a saw and meat hooks on the Garland farm.

Through what Faulkner described as "dumb luck," a mapping plane that flew over the Garland property on July 1 and 2, 2014, took photographs that show what the Crown believes to be three bodies in the grass of two adults and a child curled up beside them.

Teeth were found on the floor at the Liknes home, and bones and a small tooth were found in a burn barrel on the Garland farm, jurors also heard last week.

Inside the Liknes's home, bloody footprints matched the shape and size of a pair of shoes missing from Douglas Garland's home, an expert testified last week.

More evidence to come

Court also heard evidence last week about drill holes in the lock on the side door at the Liknes home that would have allowed entry.

Jurors will hear evidence that Garland did computer research on the same lock that was tampered with, Crown prosecutors have told them.

Forensic analysis of Garland's computer hard drive will be presented as evidence, showing someone researched topics such as "how to kill without emotion," torture, and autopsies, prosecutor Vicki Faulkner told the jury in her opening statement.

Lawyers Kim Ross and Jim Lutz are representing Garland. Faulkner and Shane Parker are prosecuting the case.