Douglas Garland's triple murder trial hears investigators collected teeth, bone and bloody bedding

• Read the latest developments from Thursday's testimony:Douglas Garland murder trial to hear about tampered lock on Liknes home
• You can also follow the latest tweets fromMeghanGrant, the CBC's reporter in the courtroom, at the bottom of this story or, if on mobile, in this live blog.

Two teeth, bloody footprints, children's pyjamas, a lock with drill marks in it and bloodstained beddingthesewere just some of the items photographed and sent for testing by aCalgary officerduring theinvestigation into the deaths ofa five-year-old boy and his grandparents.

Const. DerekAlexonfrom the forensic crime scene unit testified on Wednesday at Douglas Garland's triple murder trial.

Nathan O'Brien, 5, was sleeping over at the home of his grandparents Kathy, 53, and AlvinLiknes, 66 when the three disappeared.

Garland, 56, went on trial in the Court of Queen's Bench in Calgary starting Mondayon three counts of first-degree murder in the deaths ofthe three family members, whose bodies have never been found. He has pleaded not guilty.

Alexontestified that police were still hoping for the best, even as he was sent in to process the suspected crime scene he was told to look for Nathan who "might be hiding" in his grandparents' bloodied home.

Kids pyjamas left behind

Inside,Alexonswabbed what was believed to be blood from droplets, smears and drag marks andsent the samples to theRCMPlab for testing.

The substance believed to be blood covered bedrooms and bedding, dumbbells in the garage, linoleum in the kitchenand carpeting in the hallways.

A photo of pinkpyjamabottomslying beside the pull-out sofa in theLiknes's basement was displayed for the jury. On Monday, Nathan's mother testified that when she left her parents' home, her son was wearing a pair of his female cousin's pink pyjamas.

Inside a black purse that wasdiscovered in a hallway was a Superman cape believed to have been given to Nathan on the last day he was seen alive.

Bits of bone believed to be found in ashes

Though most of Alexon's testimony was in relation to the evidence and exhibits gathered at theLikneshome,healso told jurors he spent time on the Garland farm.

Nine months after the initial search of the property,Alexonreturned and seized six barrels of ashes from a burn pit on the farm.

He then spent the next several weeks sifting through every bit of ash and collecting materials that appeared to be bone, which were sent away for testing.

More details about the lab and test results of the evidence gathered byAlexonwill come out through other witnesses, jurors were told.

Nathan'simpromptusleepoverwith his grandparents took place on June 29, 2014. It was the last day any of them were seen.

It was Nathan's mother, Jennifer O'Brien, who discovered the empty home had several "pools of blood" inside when she arrived to pick up her son the next day.

An Amber Alert for Nathan was quickly activated, sparking a two-week searchuntil police arrested and charged Garland with murder on July 15, 2014.

A years-long grudge

At the time of the family's disappearance, Garland was living with his parents on their rural property just north of Calgary.

The Crown's theory is that the bodies of theLiknesesand Nathan were burned in a barrel on the Garland farm.

Garland is connected to theLiknesfamily through his sister Patti, who was in a common-law relationship with AlvinLiknes'sson, Allen.

Garland'ssister and his parents testified as Crown witnesses Tuesday, telling jurors of a years-long grudge Garland had against AlvinLiknesbecause of a short-lived business relationship that soured.

• Douglas Garland's sister pointed police to her brother as suspect, jurors in triple murder trial hear

Prosecutor Vicki Faulkner said in her opening statement Monday that Douglas Garland "methodically and obsessively" researchedAlvin and KathyLiknes.

When he learned the couple planned to move to Edmonton, Faulkner said Garland decided to act on his grudge.

• Douglas Garland killed Calgary couple and grandson over 'petty grudge,' court hears

Photos believed to show bodies

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, said Faulkner.

Jurors also heard that DNA evidence from the missing family members was found on a saw and meat hooks owned by Garland, and bones and a tiny tooth were discovered in a large burn barrel on the Garland farm.

Through what Faulkner described as "dumb luck," a mapping plane that flew over the property on July 1 and 2, 2014,took photographs that show what the Crown believes to be three bodies in the grass.

The trial is being presided over by Justice David Gates and is expected to take five weeks.

Garland's defencelawyers Kim Ross and Jim Lutz have not yet had a chance to cross-examine Alexon, that will take place on Thursday.

On Thursday, prosecutors will call three witnesses two lock experts and one expert in network routers.

• Get the latest updatesfrom thetrial via live tweets fromMeghanGrant, theCBC'sreporter in the courtroom.On mobile? You cansee thelivebloghere,