“His murder underscores the reality of the black experience in America.”

Only three days after former Dallas police officer Amber Guyger was sentenced to 10 years in prison for killing Botham Jean, an unarmed black man who was shot in his own apartment, a key witness in the trial was also murdered.

“Joshua Brown, the next door neighbor of #BothamJean was killed last night after being shot several times by an unknown assailant. Local media have began reporting on the shooting but have not confirmed Brown’s identity,” wrote Lee Merrit, the lawyer for Jean’s family. “[…] An ADA has confirmed that it was in fact Brown who was killed although they have yet to identify a suspect or motive for the shooting. The case is now in the hands of the Dallas Police Department.”

Brown gave testimony that was crucial in convicting Guyger and now, Lee Merritt, his family’s lawyer told CBS News Brown would have also been a key witness in a civil case filed by Botham Jean’s family against the Dallas Police Department.

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

Merritt added that Brown, who was shot at a different apartment complex than where he, Guyger and Jean lived, had been nervous someone was after him after witnessing a separate shooting incident in Dallas a year ago.

“He had been shot less than a year ago and someone standing near him was killed,” Merritt said. “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.”

Joshua Brown Hears Botham Jean Shooting

Guyger, who lived in the same apartment complex as Jean and was off-duty at the time of the shooting, walked into the his apartment and mistook it for her own. She thought Jean, who was watching television and eating ice cream, was an intruder and proceeded to kill him. Jean was a 26-year old accountant and lead gospel singer at his church.

Brown’s testimony was instrumental in undermining Guyger’s defense. Guyger claimed she said “Let me see your hands” before she shot Jean, which Brown denied, saying it sounded like “two people meeting by surprise,” before the former officer shot and killed the 26-year old man.

“Amber claimed she shouted commands to Botham before shooting him,” Merritt wrote on Facebook. “She didn’t. No one heard that. No neighbors. No passerby’s. Not Joshua as he walked down the corridor. No one.”

“She was crying,” Brown said during the trial. “Explaining what happened, what she thought happened. Saying she came into the wrong apartment.”

Brown was a 28-year-old entrepreneur and former University of South Florida football player. The Dallas police department has not yet determined a suspect in his murder.

“The complainant was found lying on the ground in the apartment parking lot with multiple gunshot wounds.  Dallas Fire-Rescue responded and transported the complainant to Parkland Memorial Hospital, where he died from his injuries,” the Dallas PD wrote in a statement to Complex. “Several witnesses heard several gunshots and observed a silver four-door sedan leaving the parking lot at a high rate of speed. There is no additional information on the suspect(s) at this time.”

Critics argue the murders of Botham Jean and Joshua Brown represent the latest example of the racism embedded in America’s justice system.

“His murder underscores the reality of the black experience in America,” Merritt wrote. “A former athlete turned entrepreneur — Brown lived in constant fear that he could be the next victim of gun violence, either state sanctioned or otherwise.”

Prosecutors revealed that Guyger, who will be eligible for parole in 5 years, made offensive statements about black coworkers and Martin Luther King Jr. in text messages.

“Damn I was at this area with 5 different black officers!!!” wrote Guyger’s partner Martin Rivera on March 9, 2018. “Not racist but damn.”

Guyger responded to Rivera, saying: “Not racist but just have a different way of working and it shows.”

Another text showed Guyger joking about a 2018 Martin Luther King Jr. day parade:

“When does this end lol,” read a text sent to Guyger. She replied: “When MLK is dead … oh wait …”

Another text refers to a dog that Guyger’s friend warned “may be racist.”

“It’s okay.. I’m the same,” wrote Guyger, before texting “I hate everything and everyone but y’all.”

Demanding Answers For Joshua Brown’s Murder

Multiple 2020 Democratic candidates spoke out after the murder, demanding answers for the strange circumstances surrounding his death.

“Joshua Brown bravely stood up to injustice and helped put Amber Guyger behind bars. Three days later, he was murdered by an unknown assailant,” tweeted Julian Castro. “We grieve with his family and friends, and demand a transparent investigation the people of Dallas can trust.”

“Just when we caught a glimpse of justice for Botham Jean, much of it feels stolen back with the murder of Joshua Brown, a key witness in the case,” tweeted Rep. Alexandria Ocasio-Cortez. “My heart breaks for his family and for everyone touched by this tragedy. We must get to the bottom of this injustice.”

In a Saturday interview with the Dallas Morning News, Jason Hermus, the lead prosecutor in the Guyger trial said Brown’s testimony was courageous and essential.

“He bravely came forward to testify when others wouldn’t,” Hermus said. “If we had more people like him, we would have a better world.”

Brown’s mother was among multiple people who suspect foul play in the young man’s mysterious murder.

“I just spoke with Joshua Browns mother. She is devastated. We all are. Joshua Brown was key witness in the murder of Botham Jean that helped put Amber Guyger away. We need answers.”

”She suspects foul play, and it is difficult to rule it out,” Merritt wrote. “He had no known enemies. He worked for a living. He was not in the streets. We need answers. Immediately.”