A joint investigation between Nassau County's Homicide Squad and Bureau of Special Operations and the Freeport Police Department led to the arrests, according to a news release.
Those arrested and their charges include:
Ramiek Smalls, 22, of 18 Rutland Rd., Freeport; murder, unlicensed operation and leaving an incident without reporting.
Michael Toney, 31, of 1049 Van Buren St., Uniondale; gang assault.
Richard Paul, 22, of 8352 261 St., Floral Park; gang assault, burglary.
Smalls and Toney were arrested Sunday; Paul on Monday, police said.
All three are scheduled to be arraigned Monday at First District Court in Hempstead.
Lawrence Hartman, 28, was pronounced dead at Nassau University Medical Center in East Meadow on May 31, about two hours after he was shot multiple times in the parking lot behind the Rumba Sky bar on North Franklin Street, police said.
The shooting began with an argument in the parking lot at about 12:35 a.m., police said. A fight broke out and then gunfire scattered a large crowd gathered for a hip-hop concert and rap battle that was later canceled, police said.
The same parking lot was the scene of a another shooting on April 17, 2010. Three people were shot in that case, which began with a dispute inside the club and then spilled outside. One victim was shot in the stomach and two others had arm wounds.