1970 mysterious light in beardstown IL

just recently i was able to salvage another sighting and document it . this one was witnessed by my grandfather and my uncle who was then 12 . my grandfather has since passed way. however my uncle told me in 1970 they were leaving their farm in plymouth Il late at night and driving through beardstown Il. my uncle stated that a mysterious and bright light came down just above the field next to their truck lighting up the ground under it. my uncle stated that the object sped up as they did and would slow down as they did. due to the delay of this report and the years it has been passed down i wish i could provide  better details but believed i should document it for those people out there who are intereted and for my grandpa.
Witness indicates that date is approximate.  One of six reports from same witness, who describes self as a public employee.  PD