Three people have been arrested and charged with murder in connection with the June killing of an 18-year-old in Hempstead.

Nassau police say 21-year-old Denis Alexander Gonzalez Sorto, 20-year-old Isaac Lopez Alvarez, and a 17-year-old juvenile are responsible for the death of Michael David Grajeda Suazo, who was attacked on the night of June 28 outside an apartment building on Fulton Avenue.

According to investigators, the three suspects, who were allegedly wearing masks, approached Grajeda Suazo from behind before stabbing, kicking, and beating him. He was transported to a nearby hospital, where he later died from his injuries.

"This is gang violence on the streets of Hempstead," Nassau County Police Detective Lt. George Darienzo said during a news briefing. "Our victim was accompanied by two 13-year-olds while he was murdered on the street."

Investigators have not identified a motive for the killing.

The arrests were made Friday night, nearly a month after the deadly assault. All three suspects were arraigned Sunday morning on second-degree murder charges and pleaded not guilty.

The 17-year-old is scheduled to return to court on the third, Lopez Alvarez on the seventh, and Gonzalez Sorto on the 10th.

"It was really sad to hear, and I was surprised to hear it was a young teen," Hempstead resident Andrew Morreale said. "It's sad and surprising that this kind of violence is still going on here," he added.