KNOXVILLE, Tenn. (WVLT) - The Tennessee Bureau of Investigation issued two Blue Alerts on Tuesday, but many are left wondering: what is a Blue Alert?. The TBI began issuing Blue Alerts on July 1, 2011. Like Amber Alerts, they are used to spread information quickly to apprehend criminals and locate missing people. Blue Alerts are specifically for the death or severe injury of a law enforcement officer where the suspect is not in custody. A Blue Alert can also be issued when an officer goes missing on duty, and foul play is suspected.