Update 4:01 p.m. IRS spokesperson Arlette Lee said the investigation is a joint effort between the IRS and the DEA. She declined further comment, stating the search warrant has been sealed by a federal court.

Federal agents guard doors of Oaksterdam University. (Photo by Rachel Dornhelm)

Update 3:12 p.m. Federal agents also raided the home of Oaksterdam founder Richard Lee but did not arrest him, according to the AP.

"Clearly, they're trying to knock down one of the leaders in the cannabis reform movement," said Oaksterdam Executive Chancellor Dale Sky Jones.

Update 11:10 a.m. The crowd protesting the federal raid in downtown Oakland has swelled to more than 60 people. KQED's Rachel Dornhelm reports Oakland police have arrived and closed down one block of 15th street between Broadway and Franklin. Federal agents are still carting evidence out of the Oakland Cannabis Buyers Cooperative and loading it into a white truck. At least one protester has been taken into custody.

Update 10:20 a.m. KQED's Rachel Dornhelm is at Oaksterdam University where about 45 people have gathered to protest. Dornhelm says agents carted out what appeared to be florescent lights and other materials broadly referred to as "evidence." Protester Maya Rise told Dornhelm, "I'm just against stealing and robbing. There are real sick people with cancer and... chronic pain that rely on cannabis. So they shouldn't be stealing people's medicine."

Original Post: OAKLAND, Calif. (AP) — Federal agents have raided a San Francisco Bay area medical marijuana training school at the heart of California's pot legalization movement.

[ad fullwidth]

The doors to Oaksterdam University in downtown Oakland were blocked Monday morning by U.S. marshals.

Agents from the U.S. Drug Enforcement Administration carted trash bags of unknown materials out of the school to a waiting van.

About a dozen protesters out front held signs demanding an end to federal crackdowns on medical marijuana.

Oaksterdam University was founded by Richard Lee, the main backer of the California ballot measure defeated in 2010 that would have legalized marijuana in the state for recreational use.

The school is in an Oakland neighborhood that has also been home to several medical marijuana dispensaries, including one founded by Lee.

Richard LeeRichard Lee

Federal Raid at Oaksterdam University