Ty Robert Scott, a 19-year-old white male from Keystone, South Dakota, died on June 13, 2018, after a gunshot tore through what had started as an ordinary night among friends. In a small Keystone apartment belonging to Cody Siemonsma, a familiar circle had gathered—watching videos, talking, drinking beer, and, as the night drifted on, handling firearms the way the group had reportedly done before.
The evening's mood shifted as guns moved from hand to hand. Testimony later described a.
38 revolver being shown around and “dry fired,” and a. 45-caliber semi-automatic pistol kept by the apartment's bed—stored with a full magazine and gear nearby—coming into the mix. At some point, Maxton Pfeiffer picked up the. 45, and he would later claim he removed the magazine and racked the slide, believing he had made the pistol safe. Then, in a sweeping motion toward the area where Scott and another friend were sitting, the weapon discharged. In the seconds that followed, voices rose in shock: witnesses recalled Pfeiffer repeating that he had checked the gun, and Siemonsma remembered hearing him insist it “should have been clear.”
For an instant, it wasn't clear who had been hit. One friend testified that he and Scott stood up and checked themselves, as if disbelief might make the danger vanish. But moments later Scott crumpled to the floor. Blood appeared, and someone yelled for a 911 call. Two frantic emergency calls followed—both later used in court—where Pfeiffer and Siemonsma described the shooting as an accident and begged for help. Pfeiffer returned inside and pressed a towel to Scott's wound until firefighters and paramedics arrived, but Scott died at the scene from a chest wound.
Investigators treated the shooting as a criminal case rather than a simple mishap. After law enforcement interviews, a deputy informed Pfeiffer that Scott had died and then arrested him. The case moved quickly into the court system: Pfeiffer faced a first-degree manslaughter charge, built around allegations that he handled the handgun in a reckless way—pointing it toward companions and firing. His attorney characterized the shooting as accidental, but prosecutors pursued the claim that the conduct met the legal threshold for manslaughter.
Years later, the story returned to a courtroom for a full jury trial. After a seven-day proceeding beginning in March 2022, jurors found Pfeiffer guilty of first-degree manslaughter. At sentencing, a judge imposed a 30-year sentence with 23 years suspended; he received credit for 180 days already served, and reporting indicated he would spend at most about six and a half years in prison under the structure of the sentence.
Pfeiffer appealed, arguing that the jury had not been properly instructed on criminal intent and that the court should have allowed a “mistake of fact” instruction reflecting his claim that he believed the pistol was unloaded. In a decision filed November 26, 2024, the South Dakota Supreme Court rejected those arguments and affirmed the conviction, concluding the instructions and the evidence were sufficient for a rational jury to find that Pfeiffer acted recklessly in the moments that ended Ty Scott's life.
