New Jersey ? A third suspect was charged Friday in the execution-style killings of three college students, hours after a man pleaded not guilty in a crime that shocked this violence-weary city.

The suspect was identified as a 15-year-old boy during a news conference held Friday night by the Essex County prosecutor’s office. The teen faces three counts of felony murder, among other charges, said Paul Loriquet, a spokesman for the office. He would not provide other details.

The latest arrest was announced several hours after Jose Carranza, 28, pleaded not guilty to three charges of first-degree murder, attempted murder and robbery. Victims’ relatives questioned why the illegal immigrant from Peru had been granted bail this year on assault and child rape charges.

A 15-year-old boy pleaded not guilty to the same charges Thursday and remains in custody, Assistant Essex County Prosecutor Thomas McTigue said. Authorities are seeking to have him tried as an adult.

Authorities said they were still looking for others involved in the shootings.