CHICAGO -- Joshua Anleu, 16, had “a cool factor” and a big smile that made him easy to recognize at Schurz High School in Chicago, where he was a sophomore. He had a thing for rap artist Playboi Carti and the video game Clash Royale, and talked about being a clothes designer or, more practically, a dental hygienist like his mom. He had a pink bike that he’d ride frequently. Earlier this month, ...