Police in Ohio got a tip that someone on Willie Nelson's son's tour bus was carrying drugs yesterday ... but here's the shocking part -- IT WASN'T WILLIE NELSON'S SON!!!
Turns out, Willie's 22-year-old kid Lukas Nelson is also a musician -- and yesterday his band was stopped in Ohio when local police got a tip that someone on the bus was in possession of some weed.
Centerville Police Department Officer Matt Dunn tells TMZ ... a drug sniffing dog was sent to the scene and tipped off police to a suspect ... a member of Lukas' band.
Cops say the band member had a small amount of weed in his possession and he was arrested for misdemeanor possession of marijuana.
As for Lukas -- dude was squeaky clean ... and after cops hauled away the band member, Lukas and his posse were sent on their way.
Lukas' dad wasn't so lucky when cops found weed on Willie's tour bus in Texas last year -- because Willie was arrested ... and the case is still ongoing.