A gang source told the Free Press that it's well known in the outlaw gang community that Maguet murdered Sylvester in a bid to take over the now-defunct Spartans motorcycle gang.
"I'm glad Joel died doing something he loved," said the source, who was a close friend of Maguet.
"Because by rights he should have been doing a life sentence."
Maguet died Monday when the small plane he flew to traffic drugs crashed into West Hawk Lake.
The source said it's also common knowledge that Maguet killed a second Spartans gang member, Robert Rosmus, in January, 1999.
"He couldn't be trusted to keep his mouth shut (about Sylvester's killing)," said the source.
The source's claims mark the first time anyone has publicly named a killer in the two high-profile Manitoba biker slayings.
Both Sylvester and Rosmus were murdered as the Hells Angels aggressively expanded into Manitoba and, in some circles, the two murders were always blamed on that expansion -- not friends killing friends.
When Sylvester vanished, he had just been released from prison and was head of the Spartans, which had an on-again-off-again relationship with the Los Brovos since 1967.
Sylvester was known to many. Flamboyant with his trademark beret and PR savvy, he once did media interviews promising to clean up crime and graffiti around the gang's Chalmers clubhouse.
Back then, Sylvester and Maguet were supposed confidantes. Maguet even ran the Spartans when Sylvester was in jail.
"He was the only other person who knew what the hell they were doing," a police source said Thursday.
Sylvester and Maguet also wanted to become Hells Angels. Maguet even did a stint as a guard for the Angels in Sherbrooke, Que., where he was photographed while under police surveillance.
Maguet also spoke French, which went a long way in building relationships with the Quebec Hells Angels, at that time a powerhouse of organized crime in Canada.
Sylvester's brother, Kevin, told the Free Press this week that Maguet had a great deal to gain by Darwin's disappearance.
"Maguet was power hungry and he didn't want to relinquish control of the Spartans when my brother got out of prison," Sylvester said. "Maguet had the most to gain by my brother's disappearance, but I don't think he was the trigger man."
Kevin Sylvester isn't saying who he believes killed his brother -- although he waged a violent war against some members of the Hells Angels back in the summer of 2002, shooting full-patch member Rod Sweeney in the head. Sweeney survived, and there were months of retaliatory attacks towards Kevin Sylvester with plenty of close calls but no deaths.
On the day of his disappearance in 1998, Darwin Sylvester had just left the Spartan's East Kildonan clubhouse on Chalmers Avenue for a meeting.
The gang source said two of the last people to see Darwin Sylvester alive were Maguet and Rosmus. Rosmus drove the car that picked Darwin Sylvester up and took him to meet with Maguet. Maguet then killed Sylvester, said the source.
On Jan. 19, 1999, Rosmus was found dead lying face up on a road east of Winnipeg. He'd been shot in the head. His body was left for all to see, as if sending a message.
That same month, on Jan. 29, Hells Angels from Western Canada met with the Los Brovos and remaining Spartan gang members at the Ichi Ban Japanese Steakhouse in downtown Winnipeg.
The Angels and the Los Brovos sat together. The Spartans sat at another table. One of the Spartans was Dan Atkinson, who was the second person killed this week in the West Hawk Lake crash. Atkinson also had full knowledge of who killed Sylvester and Rosmus, according to the gang source.
At the end of the dinner meeting it was agreed the Los Brovos would turn in their gang colours in exchange for the red and white of the Hells Angels, under the wing of the West Coast HA. The Spartans no longer existed.
-With files from Aldo Santin