The 15-year-old boy was arrested on Sunday and charged with five counts of attempted murder and criminal possession of a weapon.
He was the final suspect police were looking for after gunfire erupted at the Mount Eden train station in February.
One man, 35-year-old Obed Beltran-Sanchez, was killed and five others were wounded amid the hail of bullets.
The five victims who were injured included a 14-year-old girl, 14-year-old boy, 28-year-old man, 29-year-old woman and 71-year-old man.
A 14-year-old boy and a 16-year-old boy were the two other suspects who were arrested.
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