Gregory Shain pleaded guilty Wednesday to a charge of involuntary manslaughter for shooting and killing his 23-year-old friend last spring while they were goofing around with a handgun.

Shain told Boise police he thought a gun he was pointing at his friend, 23-year-old Gary Dean Arlen Jr., wasn’t loaded when he shot and killed him March 19, according to court records obtained by the Idaho Statesman.

Ada County prosecutors dropped a gun charge as part of a plea agreement with the 22-year-old Shain. Fourth District Judge Pat Owen is set to sentence Shain March 8. Prosecutors are recommending Shain be placed on probation for 10 years. Shain can ask for a lesser sentence.

Defense attorney Mark Manweiler told a judge in June the manslaughter charge was not appropriate since Shain made sure to unload the gun before he and Arlen were handling it that night. Manweiler said Arlen reloaded the gun without Shain’s knowledge, and when Shain fired the fatal shot, he thought the gun was not loaded.

Manweiler also said Arlen was taking narcotic prescription medication that night — saying Shain had a photo on his cell phone of Arlen using a needle to shoot up. Shain told police that when he pointed the gun, which he thought was unloaded, at Arlen, his friend put his mouth around the barrel of the gun and said “do it,” according to court testimony. Manweiler also said the gun had Arlen’s teeth marks on it.

Shain told police he and Arlen had “dry-fired” the gun before. Prosecutors say Shain had to know that Arlen re-loaded the gun and that his actions clearly met the burden of proof for involuntary manslaughter.

Manweiler said Shain had three 16-ounce cans of Coors Light that night over a period of three hours. A Boise police officer who testified during a preliminary hearing in June said while he detected a slight odor of alcohol on Shain the night of March 19, he did not order a drug or alcohol test for Shain because he did not appear intoxicated.

Shain and Arlen were friends who went to high school together and worked at the same hospital at the time of the fatal shooting.

Boise police originally charged Shain with voluntary manslaughter — the unlawful killing of a human being “upon a sudden quarrel or heat of passion.” But prosecutors changed that charge to the lesser count of involuntary manslaughter. Idaho law allows that charge when the “operation of any firearm or deadly weapon in a reckless, careless or negligent manner produces death.”