"It is much more than a protest," Ammon Bundy wrote on Facebook, two days before he and a group of people led an armed takeover of the Malheur National Wildlife Refuge. It would last 41 days.

Twenty-six people have been indicted in connection with the takeover. Nine have pleaded guilty. A 10th — Joseph O'Shaugnessy — pleaded guilty on Monday morning. O'Shaughnessy appeared in federal court in Portland to plead guilty to one count of conspiring to impede federal employees from doing their work.

It is part of a plea deal that will also settle charges against him in Nevada where he is charged in connection with the 2014 standoff with Bureau of Land Management officers at Bunkerville who were trying to impound cattle belonging to Cliven Bundy, father of Ammon and Ryan. When O'Shaugnessy is sentenced in Oregon in December, it's expected that he will receive 12-15 months in prison that will be served at the same time as the six years that he is expected to receive in Nevada.

O'Shaughnessy, who is known as "Captain," helped provide security at the refuge, though he maintains he never spent a night there. He said he agreed with the protesters' message but not the takeover of the refuge. The remaining 16 people are scheduled to go on trial in two separate groups — one starting Sept. 7 and the other group on Feb. 14, 2017.

O'Shaughnessy is one of seven people charged in both Oregon and Nevada. He is the fourth to plead guilty.

In preparation for the September trial — against Ammon Bundy, his brother Ryan, Shawna Cox, Pete Santilli, David Fry, Jeff Banta, Kennth Medenbach and Neil Wampler — prosecutors on Friday filed documents previewing their case.

"Through their combined efforts, these men and women would steadily fortify their hold on the property, as its employees stayed away in fear," prosecutors wrote. These efforts, say prosecutors, included: replacing Fish and Wildlife Service signs with their own; taking over the kitchen; sleeping in the bunkhouse; driving Refuge-owned vehicles; breaking into safes; stealing gas; attempting to access employee computers; using heavy equipment to build a road; building a bunker; and digging a trench that they filled with trash.