According to Spota, investigators were able to tie the gun to the crime with ballistics evidence. He said the gun's serial number was defaced but that investigators were able to retrieve it.
The gun was seized on March 24 as part of an ongoing weapons crackdown on Long Island.
During the undercover investigation that led to the seizure, Spota said the suspect, Alvaro DelGado of Bay Shore, N.Y., indicated that the gun has "has 10 bodies on it."
Law enforcement authorities from at least two other jurisdictions outside New York have expressed interest in examining the gun for possible crimes in their area, including one double homicide, Spota said. He did not identify those jurisdictions.
Killed in the Newark attack were Terrance Aeriel, 18; Dashon Harvey, 20, and Iofemi Hightower, 20, all of whom were shot in the head after being ordered to kneel in front of a wall, authorities said.
Aeriel's sister, Natasha, was shot in the head but survived and helped police identify at least one of the suspects. Police have said she is currently in a witness protection program.
Spota said DelGado is a high-ranking member of the El Salvador-connected MS-13 gang. Some of the six suspects in the Newark schoolyard slayings were thought to have ties to the gang, though local authorities have downplayed those allegations.
MS-13, which stands for Mara Salvatrucha, originated in Los Angeles among immigrants from El Salvador in the 1970s and 80s and has since spread to parts of the U.S. and Central America, where it is involved in human trafficking, kidnapping, and drugs and weapons smuggling, according to federal authorities.
According to authorities, DelGado was storing the revolver - which had five rounds in its chamber when it was recovered - and a loaded, sawed-off shotgun in a dresser when they were seized.
DelGado, 25, faces two counts of criminal weapons possession and one count of criminal sale of a firearm. He was being held in lieu of $200,000 cash bail.
All six suspects in the Newark killings - three adults and three juveniles - were arrested within two weeks of the killings and pleaded not guilty. They are awaiting trial.
At the time of killings, the Aeriels and Harvey were students at Delaware State University, while Hightower was in the process of enrolling there for the fall semester.
