Robert Leroy Anderson was born on December 4, 1969, in Sioux Falls, South Dakota. He was the third son of Leland and Ruth Anderson. The family moved to Groton during his childhood, where his younger sister was born, before returning to Sioux Falls in 1976. Anderson attended Hayward Elementary School and later Washington High School.​

In 1986, Anderson moved to Kansas City, Missouri, with a friend's family but dropped out of school shortly after. He worked at an amusement park, operating a rollercoaster, where an accident occurred, though he was cleared of any wrongdoing. Returning to South Dakota in 1987, he worked at a restaurant and later married 17-year-old Elizabeth Ann Nielsen in 1989. The couple divorced shortly after the birth of their first child in 1990. Anderson had three more children with Elaine Edna Gardner, whom he married in 1992. ​

On August 27, 1994, 29-year-old Larisa Dumansky disappeared after her night shift at the John Morrell & Company meatpacking plant in Sioux Falls. Her car was found in the parking lot with flat tires and keys hanging in the door. The case went cold until 1997 when Anderson's friend, Glenn Walker, led authorities to a shallow grave containing Dumansky's remains. Anderson had abducted her at knifepoint, raped her in a field, and suffocated her by wrapping duct tape around her head. ​

On July 29, 1996, Anderson abducted 28-year-old Piper Streyle from her home in Canistota, South Dakota, in front of her two young children. He had previously visited the family under the pretense of interest in their Bible camp. After the abduction, a search of Anderson's trailer revealed blood-stained jeans, handcuff keys, a pocket knife, and other incriminating items. DNA testing confirmed the presence of Streyle's hair in his vehicle. Despite extensive searches, her body was never found.

In 1997, Anderson's cellmate, Jeremy Brunner, provided authorities with detailed confessions from Anderson about both murders. Anderson considered himself a serial killer and had kept items from his victims. He was convicted on April 6, 1999, for the murders of Dumansky and Streyle and sentenced to death on April 9, 1999. On March 30, 2003, Anderson committed suicide by hanging in his prison cell.