The Associated Press corrected that the Sioux Falls death was not a shooting and the suspect's last name in the last sentence.
Separate homicide cases are proceeding in three South Dakota cities: Sioux Falls, Rapid City and Peever.
No arrests have been made in the recent deaths of 33-year-old Eustacio Marrufo at a Rapid City hotel and 50-year-old Cresencio Conde-Vargas in his Sioux Falls home. But authorities say they believe the victims knew their attackers, and that there isn't any danger to the public in either city.
A judge has set bond at $250,000 for the suspect in the Peever homicide. Twenty-three-year-old Patrick Hopkins is charged with first-degree murder in the stabbing death of Adam LaFramboise at a home in the northeastern South Dakota community. Hopkins could face death or life in prison if convicted.
This article has been revised to reflect the following correction: