"This has been a tough few days for Los Angeles," Los Angeles Mayor Eric Garcetti said, speaking of Hussle's advocacy for the community.
Garcetti also urged the public not to commit revenge killings in light of the murder.
The LAPD is seeking the public's help in apprehending Holder.
Anyone with information is urged to contact South Bureau Homicide Detectives at 323-786-5100 or the L.A. Regional Crime Stoppers at 1-800-222-8477.
Early Monday morning, authorities announced that an arrest warrant was out for Holder, a 29-year-old Los Angeles resident with alleged gang ties.
Holder allegedly shot the Grammy-nominated rapper and two others on Sunday afternoon outside of Hussle's retail store in a South Los Angeles strip mall.
The suspect then fled the scene in a white 2016 Chevy Cruz that was driven by an unidentified female accomplice, according to the release. The vehicle’s California license plate was reported to be 7RJD742.
Two of the victims were transported to local hospitals for their injuries, the release said. Hussle, whose real name was Ermias Asghedom, died at the scene. He was 33 years old.
Holder was reportedly an acquaintance of Hussle, with whom he'd allegedly gotten into a disagreement before the shooting.
A vigil for the slain rapper was held Monday, where several individuals were injured after false reports of shots being fired led to mass panic.
Story developing ...
Fox News' Bradford Betz contributed to this report.