Simple, have a quick conversation chapter one of the sequel.
“Where’s Joe?”
“Six years in prison, because when they say NO PARKING, the really mean NO PARKING.” or
“Got transferred to far, far, away.” or
“He learned why there’s safety bars on woodchippers. Coroner estimated they recovered 60% of the remains.”
And if you want the villain to be a surprise, have his whereabouts accounted/dismissed for in this conversation too.