The mysterious case of the missing autistic boy who has haunted the imaginations of New York subway riders since early October may be coming to a close, police authorities report. After the skeletal remains of a left arm and legs were found Thursday night on a beach in northern Queens, near the Bronx-Whitestone Bridge, police began combing the East River and Queens’ shoreline in search of a possible connection to 14-year-old Avonte Oquendo, who was last seen leaving his school around 12:30 p.m. on Oct. 4, 2013. Family lawyer Daniel Perecman told NBC News law enforcement officials contacted the Oquendo family after finding the remains on the rocky shore as well as nearby clothes that matched the description of those worn by the Queens teenager, who cannot communicate with words.

Unable to make a positive identification, the investigation continues while the medical examiner works to determine a cause of death in the Queens County Morgue. In Rego Park, Queens, Vanessa Fontaine, Oquendo’s mother, waited for news, having previously hoped her son was being held by a kidnapper. The location where the human body parts were discovered is several miles from Oquendo’s school in Long Island City, where he was last seen.

“This has been an unimaginably grim and horrific time for her and her family,” Perecman told PIX11 News, adding that she should hold out hope until everything has been confirmed. A 911 call at 7:16 p.m. alerted the police to the discovery of a possible arm and legs that had washed up on the rocky shore. A police source told the New York Post that the 14-year-old girl who discovered the remains tweeted about it first before placing her call to the authorities.

“Instead of calling 911 right away, she got on Twitter and talked about it,” the source told the Post. “Then she finally told her mom, and they called 911.” An Emergency Service Unit, harbor units, and a scuba dive team began a search for additional remains and clothing early Friday morning.

Initially, the New York City subway system had been the focus of an extensive search because his mother told police the autistic boy is fascinated by the underground train system. On the day he slipped from sight, three adults had been watching as his class journeyed to the computer lab. As previously reported by NBC News, security cameras showed Oquendo walking by the main security desk twice before he left through an exit door ajar in the back of the building. Just minutes later, a school safety agent closed the door. Posters with the attractive teen’s face had been posted nearly immediately throughout the New York city subway system, where commuters were often seen studying his features in hopes of aiding the search.