Police are investigating a possible link between hip-hop star Fabolous and the murder of an upstart rapper near a Queens nightclub, the Daily News has learned.

NYPD detectives aren’t sure what role, if any, the Brooklyn rapper might have played in the March killing, but a surveillance video shows Fabolous leaving Club Amazura seconds before a mystery gunman blasted Greg (G-Baby) Brown in the back.

“[Fabolous] is about to get in the car as the shooting goes down,” said a police source who watched the video.

Police and G-Baby’s relatives say the rappers – both from Bedford-Stuyvesant – had a longstanding beef, though a source said they’d put it behind them.

“My son was going to talk to Fab in a car, and he got shot three times,” grieving mother Roxanne Brown said. “I don’t know what’s going on. I just want to know who killed my son.”

Homicide investigators have yet to interview Fabolous, whose real name is John Jackson, and won’t until they get more information on his possible connection to the slaying. Police haven’t made an arrest in the March 13 shooting, and Fabolous hasn’t been named as a suspect.

Fabolous’ spokeswoman, Tammy Brook, declined comment. His lawyer, Alberto Ebanks, didn’t return calls.

G-Baby, 22, was a protégé of rapper Memphis Bleek, a Brooklyn artist who rose to stardom in the 1990s. Memphis Bleek signed G-Baby to his record label, Get Low Records. G-Baby used his ties to Memphis Bleek to schmooze with the likes of Spike Lee and Jay-Z.

News of the young rapper’s murder spread on the Internet after Fabolous wrote about it on Twitter seven hours after the shooting.

“Lost a soldier in the field this morning,” he tweeted. “R.I.P. G Baby.”

The night of the murder, G-Baby went to Club Amazura in Jamaica, Queens, without his posse, which normally would have included Memphis Bleek. G-Baby was asked to perform onstage while the crowd of 1,900 revelers anxiously awaited Fabolous’ arrival.

Fabolous got there around 3a.m., said former NYPD hip-hop crimes investigator Derrick Parker, who was at the concert helping with security. Fabolous left the stage an hour later, Parker said. Soon after he left the club, there was gunfire at Archer Ave. and 143rd St.

G-Baby was shot in the back, and a person cops said was an innocent bystander was wounded in the groin. The second victim, a 20-year-old man, survived.

Parker has worked with detectives from the 103rd Precinct and the NYPD’s intelligence unit acting as a bridge between the hip-hop community and police.

“G-Baby and Fabolous had beef before, but they supposedly squashed all of that,” Parker said.

Roxanne Brown said she wants to stay away from any rap-world drama and just focus on helping cops find her son’s killer.

“I don’t want to talk to Fabolous,” she said. “I want whoever did this to pay.”

Anyone with information on the shooting should call Crime Stoppers at (800) 577-TIPS.