Porcupine Man Sentenced to Eight Years in Federal Prison

RAPID CITY - United States Attorney Alison J. Ramsdell announced today that U.S. District Judge Karen E. Schreier has sentenced a Porcupine, South Dakota, man convicted of Involuntary Manslaughter and Assault Resulting in Serious Bodily Injury. The sentencing took place on March 29, 2024.

Robert Cottier, 65, was sentenced to two eight-year terms in federal prison, to run concurrently, followed by three years of supervised release, and ordered to pay a $200 special assessment to the Federal Crime Victims Fund and restitution. Eight years is the statutory maximum for involuntary manslaughter.

Cottier was indicted for Involuntary Manslaughter and four counts of Assault Resulting in Serious Bodily Injury by a federal grand jury in May of 2023. He pleaded guilty on January 3, 2024.

The convictions stem from Cottier operating a motor vehicle on February 18, 2023, while under the influence of alcohol, causing a head-on collision with another vehicle. The collision killed one man and injured four others, three of which were minors. Cottier’s BAC was approximately between .128% and .198% at the time of the collision.

This matter was prosecuted by the U.S. Attorney’s Office because the Major Crimes Act, a federal statute, mandates that certain violent crimes alleged to have occurred in Indian Country be prosecuted in Federal court as opposed to State court.

This case was investigated by the FBI and the Oglala Sioux Tribe Department of Public Safety. Assistant U.S. Attorney Anna Lindrooth prosecuted the case.

Cottier was immediately remanded to the custody of the U.S. Marshals Service.