Three men have been indicted in the slaying of a key witness in the murder trial of Amber Guyger, the white former Dallas police officer who was sentenced to prison this fall for fatally shooting her unarmed black neighbor.

The witness, Joshua Brown, was shot to death 10 days after he testified against Guyger, fueling rumors that his role in the closely watched trial made him a target.

A Dallas County grand jury charged Michael Diaz Mitchell, 32, Jacquerious Mitchell, 20, and Thaddeous Charles Green, 22, with capital murder in connection with Brown’s death, records show. The indictments, first reported by the Dallas Morning News, were issued Thursday but weren’t made public until this week.

The Mitchells, who are uncle and nephew, were arrested in October and are being held in the Dallas County jail. Green has not been arrested. Attorney information for the suspects wasn’t immediately available.

The indictments open a new chapter in a tumultuous legal saga that has inflamed tensions between law enforcement and African Americans in the Dallas region, where distrust of the police runs deep in the black community.

Police have adamantly denied that Brown’s killing was somehow connected to the Guyger trial, saying the 28-year-old was gunned down in a drug deal that went awry.

“There’s been speculation and rumors that have been shared by community leaders claiming that Mr. Brown’s death was related to the Amber Guyger trial and somehow the Dallas Police Department was responsible,” Assistant Police Chief Avery Moore said at an October news conference. “I assure you that is simply not true."

But the assurances haven’t satisfied some local leaders, including Lee Merritt, a civil rights attorney representing Brown’s family, who said the proximity of Brown’s killing to the trial implicated police and undermined their credibility. Merritt told The Washington Post on Monday that he wants the department to recuse itself from the investigation and let a “disinterested party” take over.

“However plausible or implausible their involvement in the murder of Joshua Brown may be, a cloud of suspicion lingers over this investigation,” he said. “A neutral party would have helped to remedy this well-settled distrust.”

Representatives from the Dallas Police Department and the Dallas County District Attorney’s Office didn’t immediately respond to requests for comment Monday.

Guyger shot and killed 26-year-old Botham Jean in September 2018 after apparently mistaking his apartment for her own and believing he was an intruder. The shooting sparked days of protests in Dallas, with many saying it fit a pattern of officers recklessly using deadly force against people of color.

Brown, who lived in the same complex, provided crucial testimony in Guyger’s murder trial a year later. He told the court that he overheard the encounter between Guyger and Jean but didn’t hear the loud police commands Guyger claimed she made before opening fire, undercutting a key part of the officer’s defense. At one point, Brown broke down in tears on the stand as he recounted how he hadn’t met Jean until the morning of the shooting but used to hear him singing gospel music in his apartment.

Guyger was found guilty and sentenced to 10 years in prison.

Days after the trial ended, with emotions still raw, Brown turned up dead of gunshot wounds.

Police said the suspects drove 300 miles from Alexandria, La., to Dallas to buy drugs from Brown. An argument ensued outside his apartment, police said, and the men exchanged gunfire. According to police, Jacquerious Mitchell told investigators after his arrest that Brown shot him in the chest and that Green returned fire, hitting Brown in the lower body. Green then allegedly took Brown’s gun and backpack, and the three suspects drove off.

Green got out of the car at an unknown location, police said, and Jacquerious Mitchell went to the hospital, where he was taken into custody.

Police said a search of Brown’s apartment turned up 12 pounds of marijuana, 143 grams of THC cartridges and $4,000 in cash.

Originally from Jacksonville, Fla., Brown moved to Texas in 2008. After graduating from high school, he returned to Florida for college and played defensive back on the University of South Florida’s football team. After graduating, he moved back to Dallas and ran a company that managed Airbnb properties.

“His murder underscores the reality of the black experience in America,” Merritt, the family attorney, wrote shortly after Brown was killed. “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.”

Brittany Shammas and Reis Thebault contributed to this report.

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