In response some leaders in Virginia City formed the Vigilance Committee of Alder Gulch and began to take action against Plummer's gang, gaining confessions from a couple of men they arrested in early January 1864.

[2] But in August 1859, supporters wrote to the governor seeking a pardon based on his alleged good character and civic performance.

On the way back east, waiting for a steamboat to reach Fort Benton, Montana, on the Missouri River, Plummer was approached by James Vail.

He was recruiting volunteers to help protect his family from Indian attacks at the mission station he was attempting to start in Sun River, Montana.

As gold had recently been discovered in nearby Bannack, Montana, Plummer decided to go there to try to earn enough money to support them both.

Notable criminal acts by alleged members of the Plummer gang included: At the time Bannack and Virginia City were part of a remote region of the Idaho Territory; there was no formal law enforcement or justice system for the area.

From December 19 to 21, 1863, a public trial was held in Virginia City by a miners' court for Ives, the suspected murderer of Nicholas Tiebolt, a young Dutch immigrant.

Shortly after its formation, the Vigilance Committee dispatched a posse of men to search for Carter, Graves, and Bunton, known associates of Ives.

Near the Rattlesnake Ranch on the Ruby River, the posse located Erastus "Red" Yeager and George Brown, both suspected road agents.

The posse found Yeager and Brown guilty and hanged them from a tree on the Lorrain's Ranch on the Ruby River.

[6] On January 6, 1864, vigilante Captain Nick Wall and Ben Peabody captured Wagner on the Salt Lake City trail.

By this time, Yeager's confession had mobilized vigilantes against Plummer and his key associates, deputies Buck Stinson and Ned Ray.

[7] On May 7, 1993, a posthumous trial (Montana’s Twin Bridges Public Schools initiated the event) was held in the Virginia City, Mont., courthouse.