The most recent threat was discovered at around 6 a.m., and prompted police to issue a bomb threat alert. No passengers had boarded the flight in question at that hour. Police searched the plane and lifted the alert at 7:18 a.m.
Tuesday’s threat followed a similar message posted to Twitter Monday afternoon. That message said, “I have a massive semi-nuclear explosive on-board flight 4200 from San Diego to Dallas -- if this fails, I will shoot the plane,'' according to NBC 7.
The flight, which left Lindbergh Field in the late afternoon and was scheduled to land in Texas in the early evening, was not diverted, according Southwest Airlines, which issued the following statement:
“Any threat or alleged threat against the safety of our employees, customers, or aircraft is a matter we take very seriously. We are working with the relevant authorities to ensure the safety of this and every flight. It is our policy not to further comment on matters of security.''