FARGO, N.D. (AP) – A man accused in a shooting that left one man dead and prompted school lockdowns and closings in northeastern North Dakota acted in self-defense, federal authorities said Wednesday.

The federal investigation into the November killing of 29-year-old Joel Sherman on the Turtle Mountain Indian Reservation showed that homicide charges are not warranted, according to U.S. Attorney Timothy Purdon.

“Many, many hours and law enforcement resources were dedicated to this investigation in order to determine exactly what occurred and to ensure that no additional threat to the community existed,” Purdon said in a statement.

Tribal prosecutors filed reckless endangerment and assault charges against Justin Keplin, 31, following the Nov. 27 shooting. Bill Marcellais, the tribal prosecutor, did not immediately return a phone call seeking comment on the status of the case.

Federal investigators said sworn statements from several witnesses who were at the scene show Sherman first fired several rounds from his pistol and Keplin then returned fire. Witness accounts were corroborated by bullet casing locations and bullet holes, prosecutors said.

The investigation showed Sherman had made death threats the day before showing up armed with a pistol at a residence in Belcourt. Sherman allegedly confronted Keplin and began an argument that continued outside the residence in Eagle View Housing.

Purdon would not say whether other charges are possible and would not comment on further details.

The shooting kicked off a brief manhunt when police said they were looking for two suspects. Authorities blocked off roads, called in air support to help with the search and put schools and other institutions and businesses on alert.

The federal government generally prosecutes homicides and other serious crimes on Native American reservations. Purdon said his office chose to publicize this case to show residents that it was “taken seriously and fully investigated” by federal authorities.