The man charged in the deaths of Calgary residents Kathy, 53, and Alvin Liknes, 66, and their five-year-old grandson Nathan O'Brien has personal and business links to the family, and a criminal history.

Douglas Garland, 54, was charged Tuesday with first-degree murder in connection with the grandparents' deaths.

He was charged with second-degree murder in connection with the death of Nathan, who was at his grandparents' home for a sleepover the night before they were all reported missing. Their bodies have not been found.

Garland's sister, Patti Garland, is in a common-law relationship with Alvin Liknes's son. His sister also lists Nathan's parents, Rod and Jennifer O'Brien, as well as Kathy Liknes (the missing grandmother) as "friends" on Facebook. One member of the Liknes family is also listed as a niece. 

CBC News has learned that Garland and Alvin Liknes were involved in a patent dispute and that there was "bad blood" between them because of business dealings that had gone sour.

Kathryn Liknes, Nathan O'Brien and Alvin Liknes

Nathan O'Brien, centre, and his grandparents, Kathy and Alvin Liknes, have not been seen since Nathan's mom left the Likneses' home the night of June 29. (Calgary Police Service)

Liknes had previously registered a patent for an apparatus that separates gas from water. Family members confirmed to CBC News that the patent was a sore point between Liknes and Garland, who had worked together in the past.

Police have confirmed they are investigating a business relationship between Garland and Alvin Liknes. 

"There are some business issues that we are looking into," Calgary Police Service spokesperson Kevin Brookwell said on July 10.

"I can't get into specifics about what these are and who was involved, what they look like or how many people were involved. But yes, we have got a number of people who are looking into that." 

Garland, who had been considered a "person of interest" in the case, was staying at a motel in Airdrie, just north of Calgary, after being released on $750 bail on unrelated charges when police arrested him Monday. 

Police arrested Garland near the acreage owned by his parents, which has been at the centre of the investigation into the disappearance of the Liknes grandparents and their grandson.

Police say he broke the conditions of his release by being in the field at night.

Garland also faces a charge of identity theft not related to the missing family investigation, and a charge of unlawfully possessing a bank card. 

Drug lab bust

After a drug lab bust on his parents' property in 1992, Garland was charged with drug trafficking, possession of stolen property and identity theft. 

After failing to appear at court in 1992 for drug charges, the then 33-year-old Garland disappeared.

A document from the Tax Court of Canada indicates Garland was later discovered living in Vancouver under the name of Matthew Kemper Hartley — a 14-year-old Alberta boy killed in a car crash in 1980. 

The same document says Garland had attended medical school in Alberta for one year before suffering a mental breakdown.

Garland told the court at the time he had been traumatized after causing what he described as a horrific accident after falling asleep behind the wheel.

Garland returned to Calgary after being discovered living in Vancouver and pleaded guilty to several of the charges in connection with the drug bust and stolen identity, while the others were dropped.

'Little violence potential to others'

In 2000, he was sentenced to 39 months for making amphetamines at his parents' farm.

The Parole Board of Canada gave him accelerated release after six months, noting in its decision that Garland's prior criminal record consisted of property offences over the course of 20 years.

His mental health played a role in the crimes, the board said, but a psychologist determined that Garland had "little violence potential to others." It ordered a psychologist and psychiatrist to closely monitor him during his release.

While Garland had confessed to stealing Matthew Hartley's identity in the 1990s, when he was hiding out in Vancouver, the identity theft charge laid against him earlier this month relates to the alleged use of that same identity.

With files from The Canadian Press