"If you know what's going on, please say something."
McKellar and her family say the body found inside a burning vehicle Wednesday night was her son Rafael Rivera, 24.
Police last night hadn't identified the body, nor ruled the man's death a homicide, but family members were certain it was Rivera after working with investigators.
A police source told the Daily News yesterday that cops arrested a man who they believe shot the victim before torching his body inside a Mitsubishi Galant on Lawrence Street near 5th, about 8 p.m. Wednesday.
Investigators early yesterday tracked down that suspect, whose identity the Daily News is withholding because he had not been charged as of last night. The man's mother and girlfriend called police to report his car - in which the victim's body had been burned - stolen, according to the source.
A clever officer convinced the suspect to meet with cops at his house on Rising Sun Avenue near Wyoming, in Feltonville, under the guise that he had to sign paperwork to report his car stolen, the source said.
When the alleged shooter arrived, cops arrested him.
Witnesses to the initial shooting positively identified the suspect to police, the source said.
Police believe that the shooting was sparked by an argument between the suspect and victim, but it was unclear what the men were fighting over, the source said.
At the height of the dispute, which witnesses told investigators happened inside the Mitsubishi as it was parked on Roselyn Street near 4th, the suspect shot the other man in the head and then sped off.
Four hours later, the car was found burning on Lawrence Street, about two blocks from the site of the alleged shooting.
Last night, a crowd of people swarmed the corner of Roselyn Street where McKellar said her son had lost his life.
A makeshift memorial had been built for Rivera, lit by the flickering light of dozens of candles. The acrid smell of fresh spray paint filled the air, courtesy of the messages scrawled in Rivera's honor on a nearby wall.
His sister, brothers and friends wept and embraced. His 2-month-old son stirred in his aunt's arms.
Amid the grief, McKellar expressed her anger.
"I couldn't even identify him, he was so badly burned," she said. "They told me there were only teeth left; I refused to go in and see him.
"I hope the police catch whoever did this to my son, because they deserve whatever is coming to them."
On Twitter: @Vellastrations