A man who testified in the Amber Guyger murder trial died Friday night after he was found shot multiple times at a Dallas apartment complex, police say.

Dallas Mayor Eric Johnson is urging people to avoid speculation and said on Twitter that he trusts Dallas police will conduct a thorough investigation into the death of Joshua Brown.

Brown, a neighbor of Botham Jean's at the South Side Flats apartments and a witness in the trial, died in the shooting, according to the district attorney's office.

Police were called about 10:30 p.m. to the Atera apartments in the 4600 block of Cedar Springs Road, near the Dallas North Tollway and Lemmon Avenue. That's about five miles from the South Side Flats.

A 37-year-old man died Friday night after he was found shot multiple times at an apartment complex near the Love Field area, Dallas police say.

Several people flagged the officers down and directed them to Brown, who was on the ground in the parking lot, police said.

Brown was transported to Parkland Memorial Hospital, where he died, police said.

The Dallas County District Attorney's office first confirmed Brown's death Saturday, while the police department said the Dallas County Medical Examiner confirmed it at 12 p.m. Sunday.

Witnesses told police they heard several gunshots and saw a silver four-door sedan speeding out of the parking lot.

Attorney Lee Merritt represents the Jean family — and now, the Brown family.

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. pic.twitter.com/5BCdkVXoQ4 — S. Lee Merritt, Esq. (@MeritLaw) October 5, 2019

"It's troubling to say the least," Merritt said. "Anytime someone is killed, it's sad. But, this murder that happened this close to a major trial against a police officer raises a lot of eyebrows and it caught me off guard."

Merritt also said it's possible Friday's shooting was not related to the trial at all.

"He had a personal beef that I'm just starting to learn about that caused him to be shot less than a year ago," Merritt said.

Brown was shot after a fight at Dallas Cabaret in November 2018. Another man, Nicholas Diggs, was shot and killed. Brown's injury was minor.

"My understand from what I'm hearing is he (Brown) was the intended target," Merritt said. "There is something there that we're learning more about."

TRT=:15Dallas County Judge Clay Jenkins weighed in on the rumors and speculation circulating on social media Sunday saying, "Dallas County, the city of Dallas and others will work to ensure a transparent and thorough investigation of the murder of Joshua Brown. Mr. Brown was not shot in the mouth or head but was shot more than one time. Many career professionals are hard at work on this case."

Dallas County, the City of Dallas and others will work to ensure a transparent and thorough investigation of the murder of Joshua Brown. Mr. Brown was not shot in the mouth or head but was shot more than one time. Many career professionals are hard at work on this case. — Judge Clay Jenkins (@JudgeClayJ) October 6, 2019

Dallas Mayor Eric Johnson also cautioned against speculation.

"If you have information, please share it with our investigators," Johnson said in a tweet. "Dallas will never be a city that tolerates acts of violence."

Police do not have a motive or any suspects, police chief U. Renee Hall said Sunday.

Brown lived across the hall from Botham Jean and met him for the first time the afternoon of Sept. 6, 2018, the day Jean was shot, Brown testified Sept. 24, the second day of the trial.

Brown grew emotional on the witness stand and said even though he and Jean met earlier in the day, he often heard Jean singing gospel music or songs by Drake when he came and went from his apartment.

Botham Jean's neighbor Joshua Brown takes the stand in the murder trial of Amber Guyger. Brown became emotional while on the stand and said he often heard Jean signing gospel or Drake songs while walking to or from his apartment.

The two met Sept. 6, 2018 because someone from the apartment's leasing office came to both of their doors early that afternoon due to a noise complaint, Brown said. He added there was not any noise.

In his testimony, Brown said he left to go watch a football game and when he returned he heard commotion in the hallway and gunshots.

No one was in custody for Brown's death Saturday morning, and police did not provide a description of the shooter or shooters.

Police had initially said that two other people drove themselves to Parkland with gunshot wounds not thought to be life-threatening, but have determined the shootings were not related.

At least two Democratic presidential candidates tweeted about Brown's murder.

"I pray for his family, his community and all those impacted by this tragedy," Sen. Kamala Harris said. "We demand answers."

Joshua Brown’s selflessness and courage brought some justice for his neighbor Botham Jean. We grieve again learning of Joshua’s murder.



I pray for his family, his community, and all those impacted by this tragedy.



We demand answers. — Kamala Harris (@KamalaHarris) October 6, 2019

"I'm heartsick for Joshua Brown's family and friends," Sen. Elizabeth Warren said. "We need answers -- and Joshua Brown and his family need justice."

I'm heartsick for Joshua Brown's family and friends. He bravely stepped forward and testified to bring some justice for Botham Jean, and peace for his family. We need answers—and Joshua Brown and his family need justice.https://t.co/RKlcPkUalz — Elizabeth Warren (@ewarren) October 6, 2019

Editor's Note: An earlier version of this report stated that police knocked on the doors of Joshua Brown and Botham Jean. The story has been corrected to state it was leasing office workers who followed up on a noise complaint.