Christopher Dorner, the former California police officer who has been the subject of a massive manhunt in the wake of three killings, received some flight training when he was in the U.S. Navy, the TSA says, and general aviation operators should use "an increased level of awareness concerning any suspicious activity." The TSA alert (PDF) said there is no specific information that Dorner is considering using general aviation, but aircraft and airport owners and operators in Southern California are asked to secure unattended aircraft to prevent unauthorized use. Any suspicious activity or aircraft theft should be reported immediately, the TSA said, to local law enforcement and the TSA General Aviation Hotline (866-427-3287).
TSA suggested that aircraft and airport owners and operators should review the TSA publication, Security Guidelines for General
Aviation Airports (PDF). In addition, the TSA Alert lists a number of suggestions, including verifying the identification of crew and passengers prior to departure, directing increased vigilance to unknown pilots or clients for aircraft rental or charters, and reporting anyone who appears to be under stress or under the control of other people.