An eight-year-old missing person cold case in Edmonton has been upgraded to a homicide investigation, The Fifth Estate has learned.

Edmonton Police Services quietly transferred the Dylan Koshman file from their missing person unit to their homicide department several months ago.

"Reviewing the whole file, reviewing the circumstances of the night he went missing, it stinks, frankly," says Staff Sgt. Bill Clark of the EPS homicide department.

"There's a strong suspicion that it's a homicide and I think we need to take it on."

Clark says in any homicide investigation, police look at the people who last saw the person alive.

"It's people close to the family," he says. "We're going to be looking at them, absolutely."

The case is the focus of a Fifth Estate documentary, The Disappearance of Dylan Koshman, airing tonight on at 9 p.m. on CBC.

Koshman, who was last seen on Thanksgiving weekend in October 2008, had moved from Moose Jaw, Sask., to Edmonton six months earlier to work as a pipefitter.

Living with cousins

The 21-year-old moved in with his two older first cousins, brothers Nick Koshman and Colin Demasson, who were renting a house on the city's south side.

On Thanksgiving weekend, Dylan was feeling homesick. He invited another first cousin from Moose Jaw — Cameron Koshman — to visit.

Dylan Koshman's cousin, Colin Demasson, wrote a witness statement for the EPS five days after Dylan disappeared. (CBC)

In his statement to police, Colin wrote that when he got home in the early morning of Sat. Oct. 11, 2008, "I confronted them [Dylan and Cameron] and told them to leave. We argued and a fight/wrestling match broke out."

Colin went on to write that after the wrestling match he continued to argue with Dylan and told him to "get out, he didn't live here anymore. Come back and get his stuff later. He left out the back."

That's the last time Colin says he saw Dylan, who has not been seen since Oct. 11, 2008.

Colin declined to give The Fifth Estate an interview for the documentary.

His brother Nick, who also declined to speak with the program, prepared a nine-page account of what happened after his aunt asked him to write it out several days after Dylan's disappearance so that he wouldn't forget anything.

Colin Demasson, second from left, and his brother, Nick Koshman, bottom right, sit with their father, now deceased. (CBC)

Nick wrote that he heard Dylan and Cameron planning on fighting with Colin when he returned home and he texted Colin to warn him.

After Colin came home, he and Dylan "went at it, pushing each other around. They make it to the floor and Dylan's been throwing punches and Colin looked like he was going more to restrain Dylan rather than hurt him."

Nick says that he turned around "to get a drink and when I came back to see, Dylan had left and Colin said he went out the back."

'He wasn't responding'

Cameron was the only person of the four others in the house that night who gave an interview to The Fifth Estate.

He said in a telephone interview that after Dylan was kicked out of the house, he hurriedly grabbed his things from Dylan's bedroom in the basement and went out the same door that Dylan left from.

According to Cameron's phone records, someone used Dylan's phone to call Cameron at 3:30 a.m. several times in the span of one minute. Cameron says he missed all the calls because he was simultaneously calling 911 to report that he was hiding from Colin, whom he alleges was trying to beat him up.

At least two neighbours also called 911 to report fighting, which moved from inside the house onto the front lawn.

I can only imagine what a nightmare that it is to not know what happened to your son. - Const. Shelley Pinch

In addition to the four first cousins, Nick's girlfriend was also in the house that night. There is no indication that she was involved in the fight.

All four — Colin, Cameron, Nick and his girlfriend — have been questioned by the police.

Sean Jenkinson, a former investigator in the EPS missing persons unit, says of all the cases he handled in his six years in the department, Dylan's is the one that haunts him the most.

When he left the unit in 2013, Const. Shelley Pinch took over. She says phone calls with Dylan's mother, Melanie Alix, regarding the case have been tough.

Const. Shelley Pinch says phone calls with Dylan’s mother regarding the case have been tough. (CBC)

"That's really a difficult part of my job," she says.

"When I call her, I know it excites her to think that when she hears my voice, 'Oh is this some new information?' and then I say you know, 'Melanie I'm just checking in, I don't have any new information,' and I can just feel and hear her disappointment.

"As a parent I can relate … I can only imagine what a nightmare that it is to not know what happened to your son. And ... a big driving force for me is what else can I do to try to locate Dylan and ... get some closure around this."

Since 2008, Dylan's family has made an annual trek to Edmonton to hold a candlelight vigil on Thanksgiving weekend to bring awareness to the case and ask for tips.

About six months ago, Pinch took the file to one of the staff sergeants in charge of the homicide department — Bill Clark — for review. It's not clear what prompted the review.

Upon reviewing the case, Clark agreed to have it transferred to the homicide department.

Pinch, left, Det. Alan Elliott and Staff Sgt. Bill Clark discuss the Dylan Koshman investigation at the EPS headquarters. (CBC)

If a person just wanders off or goes missing, "we usually find them," Clark says.

"There's been various stories about that. You know, if you get hit by a car and wander off, you're gonna be found somewhere. It just doesn't make sense."

Clark says he doesn't believe some of the individuals the EPS interviewed have been upfront with police.

"I think we have people who've lied to family members. I think we need to get to the bottom of it. We need to really find out what happened to Dylan and bring closure for this family."

Clark says he thinks Dylan was killed the night he went missing. "Can I prove it yet? No. Will I prove it? I hope so. I do believe we will."

'I don't want it to be any relative'

When informed of Clark's comments, Dylan's mother Melanie Alix burst into tears.

"It hurts because I don't want it to be any relative that could harm another person," she says. "I want to find Dylan."

Dylan's parents, Dan Koshman and Melanie Alix, watch video of a Fifth Estate interview with Staff Sgt. Bill Clark. (CBC)

Dylan's father, Dan Koshman, doesn't believe any of his relatives are involved.

"That doesn't change my mind at all," he said after hearing Clark's comments. "I don't believe that they had anything to do with it, no."

The EPS won't say whether they have uncovered any new information or received any new tips once the case was transferred to the homicide department.

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