I recently watched the film Rebel Ridge (2024), where local police unjustly seized the protagonist's money under suspicion of being drug currency. Initially, I thought this was just fictional movie drama. However, after watching an Institute for Justice YouTube video about a Marine who had his money taken based on flimsy evidence, I realized that civil forfeiture is an actual legal process in the US.
From what I gathered from the Institute for Justice video, when state or local police seize cash or property, federal law enforcement takes over the forfeiture process. The federal agency handles the paperwork and legal proceedings, then kicks back up to 80% of the seized assets to the state agency that initially confiscated them.
In Rebel Ridge, the local police held onto the seized money for 3-4 days. This surprised me, as I would have expected them to hand it over to a federal agency, like the DEA, as soon as possible.