Officer Stevens was not the only policeman to see the vast UFO that night. Police departments in Highland, Lebanon and Shiloh, all east of St Louis, tracked the craft.

One Lebanon officer called the National UFO Reporting Center hours later and said he had pursued the object at high speed, with his flashers blazing, until the unknown craft changed course to meet him.

The noiseless, dark triangle hovered above his car at 1,000- 1,500ft, as though studying him, before streaking away to the west, seeming to cover several miles in just a few seconds.

Many UFO experts believe that the silent triangles are part of a secret US military project. This one was certainly sighted within two or three miles of Scott Air Force Base. But why a secret aircraft would fly low over built-up zones with all its lights burning is a tough question.

Officer Stevens's priceless report is online at the Millstadt station site. He added a sketch to his report, showing a boomerang shape with big headlamps, and also attached a Polaroid that reveals a scattering of yellow lights in a mottled sky. The morning was bitterly cold, Stevens reports, and "the picture did not seem to exit the camera properly".

"The object was flying very low," he records, "from 500ft to 1,000ft, and was flying very slowly. The object was making no noise. I could only hear a very low-decibel buzzing sound. Then the object began banking to the northeast, and continued to cruise away from me."

Millstadt officers are not commenting on the case and simply refer callers to their website.

A local newspaper reporter, Heather Ratcliffe, says: "The police don't believe the sighting was a visitor from outer space. But they won't make any assumptions about what it is."

One thing must be certain - Officer Stevens would not threaten his own career and expose himself to ridicule by filing such a report unless he was sure it was accurate.

www.millstadtpolice.homepage.com/aircraft.html