DALLAS (CBSDFW.COM) – There are new calls for an outside investigator to look into the murder of a man who testified during the murder trial of fired Dallas Police officer Amber Guyger.

Joshua Brown, 28, was shot and killed around 10:30 Friday night in a parking lot at the Atera Apartments in the Oak Lawn area of Dallas.

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He had been shot multiple times in his lower back.​

Joshua Brown

“Josh’s heart touched a lot of people,” said childhood friend Donte Anderson. “When you lose somebody like that, a little piece of everybody he touched is gone, too.”​

For a city taking its first tentative steps towards healing, the murder of Brown ripped the bandage off of a still fresh wound.​

The world watched as Brown tearfully told jurors about his neighbor, Botham Jean and how he sang gospel music from his apartment. He also testified that he did not hear the fired former officer give verbal commands before opening fire.​

When word spread of Brown’s murder, the timing was more than troubling.

Some in the community feared that he had been targeted because of his testimony, but family members say Brown had been concerned about a nightclub altercation late last year.​

“Members of Joshua’s family have expressed to me, and his close friends, that there were ongoing threats related to the Nov. 2018 shooting at the Dallas Cabaret,” says Civil Rights attorney Lee Merritt.​

The shooting in the parking lot of the Dallas nightclub killed Nicholas Shaq’uan Diggs of Lancaster and wounded Brown.

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Kendall Morris was later arrested, indicted for murder and released on bond. Meanwhile, critics say the community needs answers from a credible source.​

“Whether they like it or not, the DPD is implicated in this murder, they’re not the correct party to investigate it. There’s no evidence linking them directly to it,” admits Merritt, but by sheer proximity and the loss of trust between them and the community, they’re not the appropriate party to investigate this case.”​

Merritt points to trial testimony concerning deleted text messages between Guyger and her married partner, Martin Rivera, with whom she was having an affair.

Critics have claimed that Guyger received special treatment following the shooting that killed her unarmed neighbor.

She was also instructed to turn off her body camera.​

The NAACP Legal Defense and Educational Fund also released a statement calling for an independent inquiry, urging officials to “follow the trail of misconduct left by the case.”​

It is, according to the civil rights group, a matter of public confidence.​

“It is critical to public confidence in the administration of justice that witnesses who speak out against police violence are fully protected,” says Sherrilyn Ifill, President of the NAACP Legal Defense and Educational Fund. “The suspicious circumstances of Mr. Brown’s killing should cause great alarm and demand an immediate and piercing inquiry.”​

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“No one moves on from this case as a unsolved murder,” says Merritt. “We need answers, and we need them to come from a reliable source.”​