South Dakota's attorney general announced on Friday, November 6, that a state investigation has found a Minnehaha County sheriff's deputy was justified in using force during the October 9 shooting in Sioux Falls in which Deputy Katherine Frank was fatally wounded — a ruling that closes the use-of-force question in one of the most painful cases the state's law-enforcement community has faced this year, while the man accused of killing Deputy Frank now faces first-degree and second-degree murder charges.

Source: Brookings Register / Office of Attorney General Marty Jackley

Attorney General Marty Jackley said a review by the state Division of Criminal Investigation (DCI) determined that the deputy's force was warranted under the circumstances. "Force was warranted under the circumstances, as the situation was dangerous and posed a threat to the deputies' safety," Jackley said. "We continue to keep Deputy Frank's family in our thoughts and prayers."

A mental-health call that turned deadly

The case began on Thursday, October 9, when three Minnehaha County Sheriff's Office deputies went to a residence in Sioux Falls to serve a mental health detention warrant on Brandon Oetken, 39. According to the attorney general's account, the warrant had been requested by Oetken's family members, who were concerned about his state of mind.

The Dakota Scout reported that Deputy Frank and the two other deputies spoke with Oetken for nearly half an hour in an effort to detain him peacefully. The conversation began in the doorway of the residence before Oetken retreated inside the house, and the attorney general's summary says he did not comply with several verbal requests to leave the house.

Source: The Dakota Scout

One shot, then four

Investigators say Oetken then pointed a firearm at the deputies and fired once, striking Deputy Frank. A second deputy fired four times, hitting Oetken. Deputy Frank died of her injuries on October 12, three days after the shooting. Oetken suffered a non-life-threatening gunshot wound, and the other deputies were not injured.

The DCI processed the crime scene, conducted a forensic examination of the evidence, interviewed those involved and reviewed available body-worn camera video, the attorney general's office said. Blood and urine tests on all three deputies came back negative for alcohol and illegal drugs.

Oetken's weapon — a .22-calibre long-rifle rimfire revolver — was recovered at the scene. His criminal history showed a prior arrest for driving under the influence and careless driving. While living in Minnesota, investigators said, Oetken had previously been contacted by law enforcement after he made suicidal statements and waved a gun in front of his mother.

Murder charges now before the court

The Minnehaha County State's Attorney's Office has charged Oetken with first-degree murder, second-degree murder and other charges. The charges are allegations: like every defendant in the United States, Oetken is presumed innocent unless he is proven guilty in court. The DCI investigation was assisted by the South Dakota Forensic Lab and the Sioux Falls Police Department, and the Minnehaha County Sheriff's Office cooperated with the review, the attorney general's office said.

Why this case reaches beyond one address in Sioux Falls

Mental-health detention calls are widely regarded by American law-enforcement agencies as among the most unpredictable duties a deputy can draw: the person at the door is, by definition, in crisis, the call usually comes from frightened family members, and officers are asked to take someone into custody for their own protection. In this case, investigators say, the deputies spent nearly 30 minutes talking before the situation turned violent — a detail that has shaped how the case is being discussed across South Dakota.

Sioux Falls is South Dakota's largest city and Minnehaha County its most populous county, and Deputy Frank's death has been felt across the region's close-knit first-responder community. Friday's ruling answers one question — whether the surviving deputy who fired will face any action for that use of force — but it does not answer the harder one now before the courts: what happened inside that house on October 9, and who is criminally responsible for a deputy's death.

What happens next

Oetken's murder case will now move through the Minnehaha County courts, where future hearing and trial dates remain to be followed. The attorney general's office has published its officer-involved shooting summary report, and the ruling means the deputy's use of force is closed as a legal matter. There have been six officer-involved shootings in South Dakota this year, according to the attorney general.