Joshua Brown — the Dallas man who was murdered after taking the stand in killer cop Amber Guyger’s trial — was gunned down in a drug deal, according to a report.

Brown, who previously lived across the hall from Guyger’s victim, Botham Jean, was shot dead Friday — just 10 days after providing key testimony about the night of his neighbor’s murder, according to police.

Now, sources have told WFAA 8 that Brown was killed by two men during a drug deal, and that a large amount of marijuana was seized from his apartment during a search.

Authorities are looking for two suspects in connection with the shooting — and have visited homes in Louisiana to search for them, according to the report.

Brown previously fled to California after repeatedly expressing concerns that testifying in the Guyger trial would put his life at risk, according to Lee Merritt, who represents the Jean family. He returned at the behest of prosecutors.

Guyger, 31, was convicted last week in Jean’s murder and sentenced to 10 years behind bars.