U.S. News report here.
Search warrant and affidavits (PDF) here.
The Tribe is being accused of growing hemp plants with too much THC in them, but the Tribe says they were upfront to the Feds about seedlings they received for industrial hemp research:
Former U.S. Attorney for North Dakota Tim Purdon is working with the Menominee tribe and blasted the raid as a “waste of resources” that “is exacerbated by the fact that the Tribe had agreed to act itself to destroy individual strains of the hemp crop that the Tribe and the U.S. Attorney’s Office agreed were problematic.”
“This misallocation of federal resources is exactly what the  Cole and  Wilkinson Memos were designed to prevent,” he said, referring to the Justice Department memos allowing states and tribes, respectively, to regulate marijuana.
The Menominee Tribe legalized marijuana back in August, but the government has not yet enacted regulations concerning its sale and production.