Botham Jean's former neighbor, witness in Amber Guyger trial, shot to death Joshua Brown, 28, had lived across from Botham Jean.

A man who used to lived next to Botham Jean, the victim of a wrong-apartment killing by former Dallas Police officer Amber Guyger, and who was a key witness in Guyger's murder trial was shot to death Friday night, according to Dallas County's District Attorney's Office.

Joshua Brown, 28, was shot several times around 10:35 p.m. Friday at the Atera apartments in the 4600 block of Cedar Springs Road in Dallas, about six miles from the South Side Flats apartment complex where Guyger killed Jean in September 2018, police said. Brown later died at a local hospital, according to ABC Dallas station WFAA.

The Dallas Police Department confirmed in a statement Sunday afternoon that Brown was found in the parking lot of the Altera apartments shot multiple times in the lower body.

Police said no arrests have been made in homicide and investigators are trying to identify a suspect in the case.

Lee Merritt, an attorney for Botham Jean's family, wrote on Twitter that he'd spoken with Brown's mother, who's "devastated."

"We all are," Merritt said.

Witnesses told police they heard gunshots and saw a silver, four-door sedan speeding out of the parking lot where Brown was shot, police said.

Police responded to the incident at approximately 10:37 p.m., according to the police report.

"Upon arrival, officers were flagged down by several witnesses directing them to the complainant's location," the police report states. "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 investigation is ongoing.

Brown lived in an apartment across the hall from Jean at the South Side Flats apartment complex in Dallas. He testified at Guyger's trial on Sept. 24 that he arrived home on Sept. 6, 2018, and heard two voices speaking excitedly just before two gunshots erupted inside Jean's apartment.

He contradicted Guyger's testimony that she asked Jean to show her his hands before she opened fire, saying on the witness stand that he never heard Guyger say that.

Brown's voice choked up with emotion as he recalled how he'd often hear Jean singing gospel songs inside his apartment most mornings.

Guyger testified that she mistakenly entered Jean's apartment believing it was her own and shot the 26-year-old accountant after wrongly suspecting he was an intruder intent on killing her. A jury convicted her of murder on Wednesday and sentenced her to 10 years in prison the following day.

ABC News' Matt Foster and Bill Hutchinson contributed to this report.