Following a four-day trial, the jury deliberated slightly more than an hour before finding William Cormier guilty of premeditated first-degree murder, the Pensacola News Journal reported.
Members of Dugas' family then read letters urging Cormier receive the stiffest sentence possible. Judge Terry Terrell gave him life in prison without possibility of parole, the newspaper said.
Cormier's brother Christopher pleaded no contest to two accessory charges last month. He received concurrent 15-year prison terms.
Police said William Cormier beat Dugas to death with a hammer in August 2012 and then, with his twin brother, tried to cover up the killing before selling much of Dugas' "Magic: The Gathering" trading cards at a gamers and sci-fi convention.
During statements Tuesday, Assistant State Attorney Bridgette Jensen said Cormier killed Dugas and stashed his body in a storage shed at his home -- and then tried to cover it up by having a landscaping crew clean up the yard and dispose of property.
The prosecution presented witnesses who said they had played "Magic" with Dugas and the Cormier twins. One witness, Dherry Day, testified he never saw the twins with their own collection, and the ones the suspects sold at the Dragon Con convention in Atlanta had belonged to Dugas.
Investigators said the brothers put Dugas' body in a storage container while they went to the convention. When they came back to Pensacola from Atlanta, they were seen removing property from Dugas' house in a rented truck, officials said.
Witness accounts indicate the Cormier twins got about $20,000 for the cards they sold.
Cormier's attorney, Richard Currey, told the jury it was not their duty to "solve this crime," but to make sure Cormier's rights are preserved.
Dugas was a reporter for the News Journal. Investigators found his body Oct. 7, 2012 -- buried in the back yard of the suspects' father's home in Winder, Ga., in a plastic container encased in concrete.