Incident #131 Sighting Report — Belleville, Illinois, 20 June 1948

This document contains a sighting report for Incident #131, which occurred on June 20, 1948, near Scott Air Force Base in Belleville, Illinois. The report, originating from the Air Technical Intelligence Center (ATIC) and associated with Project Grudge, details an observation made by a USAF pilot at 2230 hours. The witness described a single, approximately round object that emitted a white light. The object was estimated to be 6 feet 1 inch in diameter and was observed at an altitude below 6,000 feet. Its flight path was recorded as moving 295 degrees south of the base, then changing to 340 degrees upon reaching the end of the base. The object's behavior was described as a 'zig-zag course.' The evaluation section of the report explicitly states that an astronomical explanation is improbable. Investigators noted that the object could not have been a fireball or a large meteor, citing the zig-zag movement, the relatively slow speed, and the absence of a flare or train as evidence against such a classification. The final conclusion reached by the investigators was that the description provided was consistent with a lighted balloon in relatively close proximity to the observer. The document also includes an 'Incident Index' extracted from the Project Grudge report, which categorizes various incidents based on Dr. Hynek's evaluations, placing Incident #131 under the category of 'Balloons or ordinary aircraft.'