If The FBI Investigates A Person for Ties to Terrorism, Should They Be Allowed to Buy A Gun? [POLL]

The terrorist who killed 49 and wounded many others was interviewed by the FBI on at least two different occasions in the past. He was interviewed for his alleged ties to terrorism but was cleared each time. The terrorist was able to pass a background check required to buy a gun. Some have questioned why this was allowed to happen. If someone is interviewed or flagged by the FBI for ties to terrorism, should they be able to buy a gun?