LEAD, S.D. (MITCHELLNOW) A South Dakota man has pleaded guilty in a federal case involving illegal firearms and a secret underground bunker. On Monday, 62-year-old Ray Steele of Lead reached a plea agreement, admitting to unlawful possession of a machine gun. In exchange for his plea, a second charge was dropped. Due to previous convictions in South Dakota and California, Steele was prohibited from owning firearms. Authorities began investigating after receiving a tip that Steele was having someone purchase gun parts on his behalf. He later admitted to converting semi-automatic rifles into fully automatic machine guns. During a 2024 search, investigators discovered seven firearms and uncovered a hidden, man-made bunker at his home. The bunker contained thousands of rounds of ammunition, a gun safe, food rations, gas masks, and other survival items. Steele now faces up to 10 years in federal prison at sentencing. For more crime stories from MitchellNow.com, click here.