In July, we told you about one California sheriff’s quietly radical experiment in regulating the growing of medical marijuana, which is legal under California law.

Under the local Mendocino County law, patients with a valid medical marijuana identification card can apply for a license to grow a maximum of 25 plants; in return a patient can purchase up to 25 zip ties for $25 each that will mark their plants as legal. Alternatively, a cooperative of four patients can grow up to 99 plants. The zip ties expire at the end of each calendar year, and any plants grown outdoors must be enclosed by a 6-foot lockable fence.

As we showed in the film, Matt Cohen, who runs a medical marijuana cooperative, was one of the first to sign up for the program, run by Mendocino Sheriff Tom Allman. But Cohen’s operation has become collateral damage in the ongoing federal crackdown on California’s medical marijuana market.

On Oct. 13, heavily armed federal agents stormed Cohen’s compound, destroying his plants and searching through his business files. But there’s a twist, as correspondent Michael Montgomery explains the video embedded above: Those same documents that allow Cohen to operate legally in Mendocino County can be used against him in a federal criminal prosecution.

The segment was produced by our partners at Center for Investigative Reporting and KQED for the PBS Newshour. You can watch our joint report, The Pot Republic, here.

Sarah Moughty