A man whose homemade explosive device detonated Monday morning as he walked through a tunnel at New York City’s Port Authority Bus Terminal is in custody and being treated for severe burns and lacerations.

New York City police chief James O’Neill identified the 27-year-old suspect as Akayed Ullah during a press conference following the explosion. Little is known about Ullah, though when asked about reports that he had made statements in support of the Islamic State, law enforcement authorities did not directly deny it, instead acknowledging generically that he made “statements” but declining to elaborate.