STURGIS, S.D. (Rapid City Journal) — A South Dakota teenager has admitted that he fatally shot a Wyoming girl during an argument last fall. The 17-year-old boy pleaded guilty Thursday to first-degree manslaughter for killing Shayna Ritthaler, a 16-year-old from Upton, Wyoming. The defendant said at his change-of-plea hearing that the two got into an argument and he shot her in the head.

In court, the defendant referred to the victim as his girlfriend. Both the prosecutor and the defense agreed to ask the judge to sentence the teen to 55 years in prison. The prosecutor told the Rapid City Journal that the two had been chatting online but met in person for the first time when he killed her in October. Sentencing is set for July.