SIOUX FALLS, S.D. (KSFY) – She grew up on a farm near Davis, South Dakota and has gone on to become a nationally renowned expert on violent crime.

Forensic sociologist Rosemary Erickson is among the first to be called to testify in headline-making murder cases.

Monday, she was the guest speaker at the Sioux Falls Downtown Rotary. Erickson shared some of her research on understanding the mind of perpetrators, as well as how and why they selected a particular place or victim.

“I work with the mind of the criminal by interviewing them, and we’ve gone into prisons and interviewed almost a 1,000 prisoners about why they do what they do and what would keep them from doing it,” she said.

Erickson has also written several books on crime and its causes.

Her latest, titled “Serial Killers and the Aftermath” explores cases involving four of the worst killers she has come across in her career.