The victim was identified as Darren Seals, formerly of St. Louis, said St. Louis County Police Department spokesman Sgt. Shawn McGuire.
Just before 2 a.m. Tuesday, county police received a call from Riverview, a northern suburb, to assist local authorities with a vehicle fire.
Upon putting out the fire, police found Seals inside the vehicle. He had suffered a gunshot wound, police said. McGuire declined to release further details, citing an ongoing investigation.
The area where the vehicle was found is a largely residential street hosting apartment complexes and single-family homes. It sits a short walk from Riverview's North Riverfront Park and the Mississippi River.
Though Seals' manner of death will conjure recollections of the November 2014 slaying of Deandre Joshua
near the street where Brown was killed, police say the two crimes appear unrelated at this point.
Joshua, too, was found dead in a car with a gunshot wound. Someone had poured accelerant on him and lit him afire, burning his arms, fingers and legs, police said at the time.
McGuire told CNN on Wednesday that the Joshua case is active and remains unsolved, but investigators have found nothing linking that case to Seals' death.
'I felt her soul crying'
Seals' Twitter bio said he was a "Businessman, Revolutionary, Activist, Unapologetically BLACK, Afrikan in AmeriKKKa, Fighter, Leader."
Describing Seals as a factory line worker and hip-hop musician, The St. Louis American reported he was highly vocal
during the Ferguson protests that followed Brown's death in August 2014.
When a grand jury declined to indict Officer Darren Wilson in Brown's killing, it was Seals seen in video footage and photos embracing Brown's distraught mother, Lesley McSpadden, as Brown's stepfather angrily told the crowd, "Burn this bitch down."
Of the moment the family learned Wilson would face no trial, Seals wrote on Instagram: "After they dropped it his mom broke down so bad it hurt my soul."
In an account provided to MTV
, Seals said, "It was like I felt her soul crying. It's a different type of crying. I've seen people crying, but she was really hurt. And it hurt me. It hurt all of us."
He included footage from the moment in a music video for his group D.O.A.'s song, "Born Targets." On it, Seals raps in front of the QuikTrip that was heavily vandalized
during the early days of the Ferguson protests, lashing out at the police response to the demonstrations.
"We was marching hands up not concerning the cops/Next thing you know, them bitches started pointing their choppers/They wanted to trip quick and start turning it up/So that f***ing QuikTrip we got to burning it up," he rhymed
'Before it became a riot...'
At the time of Brown's death, Seals lived just a few blocks from the Canfield Green apartment complex in Ferguson where the unarmed 18-year-old was shot. In a 2014 interview, he described to The Nation how the community quickly came together before the protests erupted, passing around a large plastic bag to collect donations for Brown's family.
"It wasn't even a protest yet. ... It was a black boy being shot in the community. It was about 10 other women and men out there, and the family," he told the magazine. "Before it became a riot, before it became a protest, it was just the community coming together."
Media outlets featured his commentary in the months to follow as he continued to be outspoken about racial issues after the Brown protests subsided. He regularly denounced police brutality and often spoke out against white privilege, while applauding those who sought to educate and empower black people.
In his last tweet, he lashed out at the NFL for its treatment of San Francisco 49ers quarterback Colin Kaepernick, who has become a lightning rod after protesting police brutality by sitting during the national anthem before games.
It was reported this week that, despite the controversy embroiling the quarterback, Kaepernick's No. 7 jersey has become the NFL's top seller
-- over the shirts worn by the Dallas Cowboys' Ezekiel Elliott and the New England Patriots' Tom Brady.
"The @NFL mad about #Kaepernick protest but I bet they don't turn down all the money from them jersey sales," Seals tweeted Monday.
Though fiery in his defense of black America, Seals' commentary could not always be placed in a one-size-fits-all box. He was highly critical, for instance, of the Black Lives Matter movement, which he accused, along with white liberal groups, of "hijacking" the Ferguson protests.
He was also critical of African-Americans who would blindly vote for Democrats. In October 2014, the Washington Post reported that Seals was "roaming black neighborhoods" with voter registration forms, urging Ferguson residents to cast their ballots for anyone but a Democrat.
"Just because they've got the D next to their name, that don't mean nothing," Seals told the newspaper
. "The world is watching us right now. It's time to send a message of our power."
He also aimed polemics at President Barack Obama, saying during the interview, "To this day, in seven or eight years, we haven't seen any significant difference in the black community."
Still, upon news of his death several protesters and others active in the black community, including those who didn't always concur with Seals, took to social media to express their sorrow.
"Him & I disagreed over much but he loved his community. Passionately. This is sad," tweeted rapper Talib Kweli.
Added Black Lives Matter's DeRay McKesson: "Nobody deserves to die. We did not always agree, but he should be alive today."