The 17-year-old was arrested Thursday and also charged with one count of attempted murder, one count of recklessly discharging a firearm and 22 counts of aggravated assault, police said Friday.
He cannot be named under the Youth Criminal Justice Act.
On Thursday, police announced Nahom Tsegazab, 19, was charged with two counts of second-degree murder, one count of attempted murder and 22 counts of aggravated assault.
Earlier this month, police announced that Shaquan (Bam Bam) Mesquito, 18, had been charged with two counts of first-degree murder and 23 counts of aggravated assault. Mesquito was also charged with the attempted murder of Tsegazab.