On the evening of October 31, 2004, at approximately 8:00 PM, three bright red lights were observed in the eastern sky over Tinley Park, Illinois, a suburb of Chicago.

This case matters because it is a documented mass event whose object identity remains unresolved.
Documented
On the evening of October 31, 2004, at approximately 8:00 PM, three bright red lights were observed in the eastern sky over Tinley Park, Illinois, a suburb of Chicago.
Debated
The identity of the object
Debated
The adequacy of the conventional explanation
Unverified
Extraterrestrial origin
Unverified
Any claim stronger than the record supports
Sources are kept in separate layers: official and contemporary material is documented; secondary UFO literature is treated as debated, not as primary evidence.
Secondary / debated material.
Documented source.
Secondary / debated material.
Secondary / debated material.
Secondary / debated material.