United Airlines flight 231 was going from San Diego to Denver when the pilot radioed in a possible threat to security. The Aribus A-320 landed in a deserted area on the DIA property mid-flight at around 9p.m.
Richard Smerker, a man who said he was a passenger on the plane, tweeted that as the plane was landing, the passengers were told not to stand up because there was a “credible threat to the aircraft.” Smerker also reported that as the passengers got off the plane, there was a group of emergency officials, cars, and K-9s to greet them.
The passengers were asked questions about whether or not they found a note, but as far as Smerker knew, no one had.
Though a spokeswoman for the DIA told 9NEWS that she could not give any details on the matter, the FBI must assess the aircraft for threats. It was confirmed that nothing was found on the plane, but the reason for concern remains undisclosed.