BOISE - A former Idaho correctional officer has pleaded guilty to two felonies in connection to an FBI drug sting, the U.S. Attorney's Office in Boise announced.

37-year-old Richard McCollough of Boise entered a guilty plea in federal court on Tuesday to two counts of possessing a firearm in furtherance of a drug trafficking crime.

McCollough was one of four Idaho Department of Correction (IDOC) officers charged in April with drug trafficking and related crimes stemming from an investigation initiated by the FBI at IDOC's request to address concerns of corruption among IDOC correctional officers.

The men all worked at the Idaho State Correctional Institution south of Boise at the time the indictments were handed down.

McCollough faces 30 years to life in prison when he's sentenced on February 25, 2019.

He is the third defendant to plead guilty in the case. Previously, co-defendants Robert Wallin, 36, and Timothy Landon, 36, both of Boise, pleaded guilty to conspiracy to aid and abet drug trafficking crimes. Both men will also be sentenced in February.

The fourth defendant, 38-year-old Erik Thompson of Star, is scheduled for trial on February 11, 2019. Thompson is charged with conspiracy to aid and abet drug trafficking crimes, distribution of cocaine, and possessing a firearm in furtherance of those drug trafficking offenses.

MORE: A violation of trust:' 4 ISCI correctional officers indicted in FBI drug sting

Court documents outline a stunning set of allegations, detailing the defendants' nine-month run of illegal activity, ranging from from packaging drugs and counting cash for their purported traffickers, to wearing their IDOC uniforms during drug transports to allay law enforcement suspicions, to soliciting the undercover officers for heroin in order to smuggle it into ISCI.

According to court records, McCollough joined in a conspiracy to assist what he believed to be a large-scale drug organization. The drug dealers he was working for, however, were undercover FBI agents. The U.S. Attorney's Office says McCollough admitted to carrying a handgun while he provided security and assisted in weighing 6 kilograms of cocaine during the sting operation.

McCollough also admitted to carrying a handgun on a separate occasion while delivering 8.6 kilograms of cocaine to an undercover officer as part of the sting operation.

The U.S. Attorney's Office noted that no drugs or other contraband were brought into any IDOC facility as part of the illegal activities.