HELENA, Mont. (AP) — Four of the six medical marijuana providers who are suing the U.S. government over last year's raids of pot businesses across Montana are being arrested on federal drug charges.

Paul Livingston, the attorney in the civil lawsuit, says four plaintiffs in the constitutional challenge of the spring 2011 raids were indicted Tuesday and last Thursday.

Livingston says those arrested were Randy Leibenguth, Luke Mulvaugh, Chris Williams and Paul Schmidt. Leibenguth's wife Stephanie also was arrested.

A fifth plaintiff was not raided last spring. Livingston says the sixth plaintiff has pleaded guilty to earlier charges.

The lawsuit challenging the constitutionality of the searches of more than 26 homes, businesses and warehouses is before the 9th U.S. Circuit Court of Appeals. Their claim was rejected by a district judge in January.