Four methamphetamine dealers and two gun-toting felons arrested as part of an investigation into the Aryan Knights gang in Idaho have pleaded guilty to charges that could send them to prison for years.

Lisa Rochel Samayoa, 45, of Boise; Darin Scott Melton, 44, of Twin Falls; Nina Ann Lucas, 32, of Pocatello; and Omar Riveroll-Hernandez, 32, of Long Beach, Calif., face five years to life in prison at their sentencing, currently scheduled for May 6 before U.S. District Judge Edward Lodge in Boise.

The four were accused of selling methamphetamine in the Treasure Valley between November 2011 and May 2012. Plea agreement details their cases are sealed in federal court.

Andrew Gallegos, 23, and Cameron James Ball, 25, also pleaded guilty to felon in possession of a firearm charges Monday at the federal courthouse in Downtown Boise. The charge carries a maximum of 10 years in prison.

Gallegos also faced a distribution of a controlled substance charge, but that charge was dismissed in a sealed plea agreement. Gallegos admitting to possessing a Smith & Wesson .357 semi-automatic pistol on Feb. 21.

Ball admitted to possessing a Hi-Point .40 semi-automatic pistol Feb. 8.

Gallegos, who is to be sentenced April 8, has 2011 felony convictions for drug possession and concealment of evidence in Ada County that prohibit him from possessing firearms.

Ball, who is to be sentenced April 9, has a drug conviction from 2005 in Ada County. He sold the Hi Point pistol and three loaded magazines to $400 to someone who turned out to be a confidential informant helping with the federal investigation into the Aryan Knights, a prison-based gang that sells drugs in southern Idaho.

The six are among 21 people charged in a federal investigation into the Aryan Knights, a gang said to be responsible for the distribution of methamphetamine in Idaho. Other recent guilty pleas include Joshua Michael Trent and Christina Shantell Massie.