Gang Member Convicted in Junior Guzman-Feliz Killing Found Dead in New York Prison

Jonaiki Martinez-Estrella, one of the gang members convicted in the brutal killing of 15-year-old Lesandro "Junior" Guzman-Feliz, was found dead in his cell at Coxsackie Correctional Facility in New York. The discovery was made around 1:16 p.m. on Friday, according to official records from the Department of Corrections and Community Supervision (DOCCS).

Martinez-Estrella, 31, was serving a sentence of 25 years to life for second-degree murder after his original conviction was partially overturned. The New York State Medical Examiner’s Office is now working to determine the exact cause of death, as standard protocol requires for in-custody fatalities.

He had been initially sentenced to life without parole in October 2019, after being found guilty of first-degree murder, a charge that included a legal determination of “torture”. During the high-profile trial, prosecutors revealed that Martinez-Estrella had delivered the fatal neck wound to Junior on June 20, 2018, leading to a wave of national outrage and renewed attention on gang violence in the Bronx.

However, in 2023, an appellate court disagreed with the original jury’s assessment regarding the torture element and reduced the conviction to second-degree murder. That ruling led to resentencing in May 2025, just weeks before his death.

The murder of Lesandro “Junior” Guzman-Feliz sparked widespread public mourning and calls for justice after surveillance footage showed the teen’s desperate attempt to escape. He was pursued through the streets of the Bronx by members of the Trinitarios gang, who had mistakenly identified him as a rival gang member. After being cornered, Junior sought refuge inside a local bodega, but was forcibly dragged out and attacked with knives and machetes on Bathgate Avenue.

Severely wounded, Junior managed to run a short distance before collapsing near St. Barnabas Hospital, where he succumbed to his injuries. His death prompted a massive social media campaign under the hashtag #JusticeForJunior, shining a harsh light on gang violence and the need for stronger community protections for at-risk youth.

The news of Martinez-Estrella’s death closes a grim chapter in the case, though other convicted members of the gang remain behind bars. His role in the crime was considered among the most severe, and his name became synonymous with the pain felt by a grieving community that has never forgotten what happened that night in 2018.

As officials await autopsy results, questions remain surrounding the circumstances of his death inside one of New York's correctional facilities. Whether accidental, intentional, or involving foul play, the event has once again thrust the Junior Guzman-Feliz case into the public eye, reminding many of a tragedy that galvanized an entire city.