The Dallas man who was murdered shortly after providing key testimony in the trial against killer cop Amber Guyger was set to take the stand in a civil lawsuit against the police department, according to a report.

Joshua Brown, 28, who was victim Botham Jean’s neighbor, was shot to death Friday night in an ambush outside his apartment in a Dallas neighborhood, according to police. No suspects have been arrested in the slaying.

“To have a key witness suddenly be killed is suspicious. Was this related to the trial? There is no clear indication,” attorney Lee Merritt, who represents the Jean family, told CBS News.

Brown’s death came days after Guyger was convicted of fatally shooting 26-year-old Jean, who she believed was an intruder when she mistakenly entered his apartment instead of her own.

Merritt said Brown would have been one of their first witnesses in the Jean family’s wrongful-death suit against the city of Dallas, which claims Dallas police failed to adequately train Guyger, according to CBS News.

Joshua Brown
Joshua BrownAP; Facebook

Brown testified at Guyger’s trial about the September 2018 night that Jean was shot dead in his own apartment. He said he heard what sounded like “two people meeting by surprise” while he was in a hallway on the floor where he and Jean lived.

He also rejected Guyger’s claims during the trial that she used commands such as “put your hands up” before shooting Jean.

“She didn’t. No one heard that. No neighbors. No passerby’s [sic]. Not Joshua as he walked down the corridor. No one,” Merritt wrote on Facebook.

Merritt has called for answers in the death of Brown, who he said lived in “constant fear that he could be the next victim of gun violence.”

“Brown deserves the same justice he sought to ensure the Jean family,” Merritt wrote on Facebook.

With Post wires