Authorities have announced that human remains found at a Queens beach last week belong to Avonte Oquendo, the missing teenager at the center of a massive city-wide search, one of the largest in New York history. The NYPD told NBC News on Tuesday that DNA tests confirm that remains are those of Oquendo, a 14-year-old boy with autism who walked out of his guarded Long Island City school in the middle of an October school day. His family has been notified, and the cause of death is still under investigation

The remains were found about 11 miles from the teenager's school, his last known location. They covered in clothing matching what Oquendo wore the day he disappeared. Last week, investigators found an arm, a torso, and a pair of legs near the Bronx-Whitestone Bridge, NBC New York reported. On Tuesday, the family's attorney announced that police also found a skull, and another arm, during a weekend search of the area. 

Virtually anyone who took public transportation in New York between October and the present will know something about the teenager's disappearance, thanks to an unusually aggressive public outreach by authorities. Trains and subway stations were plastered with Oquendo's photo and conductors made regular announcements describing the teenager — who could not communicate verbally — and how to get in touch with authorities if he's spotted. As the New York Times explains, Oquendo was known to like trains, leading those in charge of the search to target the city's transit system. 

The discovery of the teenager's remains will only lead to more questions in an investigation with few answers. The family's lawyers, referring to an internal Department of Education investigation into his disappearance, want to know how Oquendo managed to evade the notice of the three adults watching his class as it made its way to a computer lab on October 4th of last year. NBC New York reports: 

Security cameras showed Avonte walking to the first floor at 12:37 p.m., the documents say. The boy walked by the main security desk twice before leaving the building through the Center Boulevard exit door, which had been left ajar. At 12:41 p.m., a school safety agent went to the same exit and closed the door shut.

Officials didn't lock down the school until 2 p.m., over an hour after the teenager walked out of the building.