I got arrested!
Seymour handed the evidence to Rick, and Rick said: "THE EVIDENCE IS COVERED WITH YOUR PRINTS! YOUR UNDER ARREST!!". Into THE LOCKUP: "INCARCERATED!!! MY MOVIE MAKING DAYS ARE OVER!"
Nudge 1Where to look
That game is lost, sorry. Load a save from before you picked up the evidence (Esc, Load).
Nudge 2A stronger push
Detectives don't touch evidence with bare hands.
Nudge 3Almost there
The things you need for this are on the island in the jungle river.
Show the solutionThe whole answer, with a video
Pick up the marked deck of cards only while carrying the rubber gloves from THE UMBABWE ISLAND (Bringing everything back from the island). Picking it up bare-handed marks it with Seymour's prints (and from then on nothing can save him at Rick's desk). The dollars don't matter: only the deck takes prints.
Why it works
The deck's first pick-up sets a flag unless the gloves are in the inventory at that moment. Rick's script checks that flag at the very end and sends Seymour to the lockup.