Joshua Brown, the Black man who was gunned down on Friday after delivering key testimony that helped convict Amber Guyger for the killing of Botham Jean in his apartment, was reportedly also set to testify in a civil case against the city of Dallas.

The Forgiveness Trap: Botham Jean’s family’s response to Amber Guyger triggers debate

The attorney for Jean’s family, Lee Merritt said while there is no motive or suspect yet named in Brown’s killing, Brown was preparing to testify in a civil action against the city filed by the family.

Brown, who used to live in the same apartment complex as Guyger and Jean, was shot several times by an unknown assailant at his new place of residence.

“To have a key witness, suddenly be killed is suspicious,” Merritt told CBS News in an interview published Monday. “Was this related to the trial? There is no clear indication.”

Brown “deserves the justice he sought to ensure the Jean family,” Merritt said.

Brown testified that he was returning home from an outing, when he heard two people meeting by surprise. He then heard two gunshots and immediately ran away. He told the court he did not hear commands like “hands.”

Jean was fatally shot and killed by Guyger after she entered his apartment in September 2018.

“He was reluctant to testify in this case because he had been shot at and he thought some people might want to do harm to him,” Merritt told CBS News.

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Dallas Mayor Eric Johnson asked people to “refrain from speculation.”

“I trust the Dallas Police Department will conduct a thorough investigation into the death of Joshua Brown,” he tweeted Sunday.

Brown’s body was found lying on the ground in the parking lot of the Atera apartment complex with multiple gunshot wounds. Paramedics took him to Parkland Memorial Hospital, where he later died, according to The Washington Post.