The first shooting happened at 4:30 a.m. Saturday at 919 Martin Luther King Jr. Boulevard.
Investigators say some 50 to 60 people were there when gunfire erupted, leaving several people injured and the club's owner, 43-year-old Charles "X" White, dead.
Then on Sunday, as crowds gathered to sign a sheet in memory of White, gunshots rang out again.
"An individual approached on foot across the street from 919 and open fire, firing several rounds toward the crowd and struck a vehicle multiple times," said Lt. Rich Frascella of the Mercer County Homicide Task Force.
A man in an SUV was shot in the head. Someone moved him to the passenger seat and drove the vehicle directly to nearby hospital.
"We don't know why the shooting occurred on Saturday morning, but we do believe the shooting on Sunday was retaliation for whatever happened in the club on Saturday morning," said Frascella.
Trenton police and Mercer County's homicide task force are investigating the shootings and asking people to come forward with information, which can be offered anonymously.
The task force can be reached at 609-989-6406.