Fort Riley ? An Army sergeant shot two of his fellow soldiers because he had grown paranoid and angry over the possibility they might inform post police about his drug trafficking, prosecutors argued Monday during a court-martial.

Sgt. Aaron Stanley, 23, of Bismarck, N.D., has acknowledged shooting the two other soldiers, but his attorneys said he acted to defend himself and a fourth soldier.

His court-martial on two counts of premeditated murder went forward Monday after he pleaded guilty to drug use, drug possession, being absent without leave and adultery.

He is charged with shooting Staff Sgt. Matthew Werner, 30, of Oxnard, Calif., and Spc. Christopher D. Hymer, 23, of Nevada, Mo., in September at a home in Clay Center, about 30 miles from Fort Riley.

Prosecutors told an eight-member military panel that Stanley’s growing drug use made him paranoid and that he and a co-conspirator manufactured methamphetamine and grew marijuana. The two lay in wait for their victims, believing they were informants, prosecutors said.

Also charged is Sgt. Eric Colvin, 23, of Papillion, Neb. A decision on whether he will face a court-martial hasn’t been made.

Colvin has worked out a plea agreement with prosecutors and has agreed to testify against Stanley, said Lt. Col. David Velloney, the chief officer for Fort Riley’s judicial system. Velloney declined to give details.

Stanley’s attorneys said he shot Werner and Hymer because Werner was threatening Colvin with a big kitchen knife. Defense attorneys said Werner had made threats against Stanley and Colvin over rumors of an affair between Stanley and Werner’s wife.

Stanley, Colvin, the two shooting victims, Werner’s wife and two of her friends were connected by their drug use, prosecutors said.

Werner’s wife, Kristen, testified for the prosecution but acknowledged during cross-examination that, “He threatened to kill them.”

Stanley admitted to having methamphetamines in his possession at his residence in Clay Center and a barracks at Fort Riley. He admitted to distributing the drug on the Army post.

The AWOL charge stemmed from Stanley being unable to report to duty when he was in jail on drug charges. He admitted adultery on two occasions with a woman who was married to another Fort Riley soldier – but not Kristen Werner.

No date has been set for sentencing on the drug and other counts. Stanley could face up to 37 years in prison.