Speaking through a Spanish interpreter, Jose Carranza said he understood the charges against him. It was his first court appearance since he surrendered Thursday to Mayor Cory A. Booker.
Carranza, 28, is being held on $1 million bail. His lawyer, Felix Lopez Montalvo, declined to comment after the 11-minute hearing.
The Newark Star-Ledger reports that Carranza already faced criminal charges for aggravated assault and weapons counts before he became a suspect in the Newark killings.
Carranza was also charged under an alias with raping a girl over a four-year period that began when the child was almost 5 years old, the Star-Ledger reports. Carranza was free on bail when he turned himself in on Thursday.
A second suspect, a 15-year-old boy, was being held pending a detention hearing. Authorities are seeking to have him tried as an adult. His name was not released because of his age.
Both have been charged with first-degree murder, attempted murder and related charges.
The shootings ratcheted up anger in New Jersey's largest city, where overall crime has declined but where killings continued at last year's pace with 60 homicides so far this year. The killings have prompted billboards in the downtown area that scream, "HELP WANTED: Stop the Killings in Newark Now!"
Essex County Prosecutor Paula Dow has said authorities hoped to arrest others they believe were involved in the killings.
The four victims, friends aged 18 to 20, were shot while visiting in a schoolyard near their homes Saturday night. Authorities have said robbery appeared to be the motive.
Terrance Aeriel, 18, Dashon Harvey, 20, and Iofemi Hightower, 20, were forced to kneel against a wall and were shot at close range. The fourth victim, 19-year-old Natasha Aeriel, Terrance Aeriel's sister, survived a wound to her head and is hospitalized. All four planned to attend Delaware State University this fall.
Officials said fingerprints on a bottle found at the shooting scene and ballistics evidence tied Carranza to the crime. Natasha Aeriel has also helped identify the suspects.
Authorities do not believe the four victims knew the suspects.
Residents and law enforcement organizations donated $150,000 to aid the victims' families and to a reward fund for information on the case.