An Oakland medical marijuana training facility, which billed itself as the nation's only marijuana university, was raided by federal agents on Monday morning, leaving the building swarming with law enforcement and taped off from all visitors.

It's not yet clear what the specific charges are, but it's probably unsurprising that the country's largest operation training medical marijuana professionals would be targeted by federal law enforcement.

Reports from local media noted that agents were seen walking from Oaksterdam University with large bags overflowing with marijuana. It is not clear if Oaksterdam University founder Richard Lee was taken into custody.

Drug Enforcement Agency (DEA) officers were accompanied by Internal Revenue Service (IRS) agents during the raid, according to the Sacramento chapter of Americans for Safe Access.

U.S. Attorneys have been using the IRS and DEA in conjunction of late, needling many shops into closing by peering into their finances, and pulling out the bulletproof vests and shotguns when that's not enough.

Oaksterdam University may have been targeted due to the volume of marijuana being cultivated there. The threshold for a mandatory minimum federal sentence of 5 years is reached when an individual can be charged with cultivating 100 plants or more. It's not yet clear how many plants were discovered by federal agents.