Fort Riley ? A military judge sentenced an Army sergeant Wednesday to 12 years in prison on drug charges but allowed prosecutors to drop murder charges for the 2004 shootings of two fellow Fort Riley soldiers.

Sgt. Eric Colvin, 24, of Papillon, Neb., pleaded guilty to three drug charges under an agreement with prosecutors. Last month, Colvin’s testimony led to the conviction of another soldier on two counts of premeditated murder.

That soldier, Sgt. Aaron Stanley, of suburban Phoenix, is serving life in prison with no chance of parole for the Sept. 13, 2004, killings of Staff Sgt. Matthew Werner, 30, of Oxnard, Calif., and Spc. Christopher D. Hymer, 23, of Nevada, Mo., at Stanley’s farmhouse outside Clay Center, about 30 miles west of Fort Riley.

Col. Theodore Dixon, the military judge, accepted the agreement between Colvin and prosecutors, which didn’t become public until Wednesday’s court martial. Prosecutors dropped two counts of premeditated murder and a conspiracy count.

However, Dixon rejected Colvin’s request to receive only a bad conduct discharge and be freed after being jailed for 293 days while awaiting court martial.

Colvin made his plea agreement in May, before testifying against Stanley, whose attorneys attacked Colvin’s credibility.

Colvin appeared stunned by Dixon’s decision to send him to prison. Before his sentencing, he said in court that he would be labeled as a “snitch” by other inmates for testifying against Stanley.

“Even though I know what I did was right, I’m still fearful of my life,” Colvin told the judge.

His mother also asked the judge to give Colvin a lighter sentence. Renee Colvin, of Mount Vernon, Ohio, said before he went to Iraq, her son had a strong faith and was told he could be a pastor. But afterward, she testified, her son’s faith wasn’t strong.

She said during a four-month tour in Iraq early in the war in 2003, Colvin’s duties included checking coffins and rolling over bodies to check for weapons.

Colvin, Stanley and the two victims were members of the 1st Battalion of the 41st Infantry Regiment, 3rd Brigade, 1st Armored Division based at Fort Riley. Both Stanley and Colvin were with Bravo Company and had served in Iraq.

Prosecutors said Stanley shot Werner and Hymer to conceal an illegal drug trafficking operation, believing the victims to be informants for military investigators. Stanley and Colvin had acknowledged manufacturing methamphetamine and growing marijuana at Stanley’s farmhouse.

Stanley also was convicted of numerous drug charges. He was acquitted of conspiring with Colvin to commit the murders.

During Stanley’s court martial, Colvin testified that he and Stanley went to the farmhouse to dispose of drugs and to avoid a confrontation with Hymer and Werner. But a fight broke out and Stanley shot Hymer and Werner.

Colvin pleaded guilty to use of methamphetamines, possession of marijuana with the intent to distribute and wrongful distribution of methamphetamines.