The Federal Bureau of Investigation has been investigating an Islamic State Iraq and the Levant (ISIL) cell known as the “Dokumacılar” since a suicide attack killed two U.S. citizens and two others on Istanbul’s İstiklal Avenue on March 19, 2016, according to revelations from a case file at the Istanbul Chief Prosecutor’s Office. Five suspects from the attack were put on trial by the Istanbul 23rd Court of Serious Crimes in connection with the attack.