The Chelsea youth shot Tuesday succumbed to his injury last night, investigators said this morning.

Roland Polacios, 17, died at Massachusetts General Hospital shortly before 11:30 last night. He had sustained a gunshot wound at about 4:30 Tuesday afternoon in the area of 20 Suffolk St. in Chelsea.

Chelsea Police and State Police detectives assigned to the Suffolk DA’s office have been investigating the shooting “non-stop” since shortly after it took place, District Attorney Daniel F. Conley said.

Chelsea Police responded to the Suffolk Street shooting scene moments after the incident and led the investigation in its aftermath. Because Polacios’ injuries were life-threatening, Chelsea Police also notified State Police detectives, who investigate all homicides in Chelsea, Revere, and Winthrop.

State Police will now lead the investigation with the support and assistance of Chelsea Police.

Conley and Chelsea Police Chief Brian Kyes urged anyone with information on the shooting to share it with authorities by calling the Chelsea Police CrimeStoppers tip line at 617-466-4880, by texting CHELSEA and their message to TIP411 from their cell phone, or by calling the Suffolk State Police Detective Unit at 617-727-8817. All callers may remain anonymous if they wish.