A fugitive task force arrested 18-year-old Raheem Simmons in Camden on Friday.
Simmons, 20-year-old Eric Darden and 20-year-old Phillip Byrd are charged with murder, carjacking and other offenses.
Authorities say 28-year-old Sunil Rattu of Old Bridge and 24-year-old Radha Ghetia of Sayreville were robbed of a small amount of cash in the Trump Taj Mahal parking garage, then forced to drive to a nearby alley, where both were shot on Sept. 18.
Rattu died from two gunshot wounds to the head. Ghetia was shot in the upper body but survived.