A Crow Agency man is under federal investigation for allegedly killing his aunt and assaulting his grandmother as she tried to stop the attack this week, according to tribal authorities.

Daniel M. Dreamer, 24, pleaded guilty Wednesday in Crow tribal court to three charges of deliberate homicide, aggravated assault and elder abuse, according to tribal court documents. He is currently being held at the Rocky Mountain Detention Center in Hardin.

According to Crow Tribal Court documents, Dreamer allegedly stabbed his aunt 22 times with a butterfly knife Tuesday night at a residence on Dakake Street in Crow Agency.

His 86-year-old grandmother tried to stop the assault, and Dreamer allegedly pushed her to the ground, according to court documents. She was taken to a local hospital with a laceration to her collar bone and an injury to her wrist that appeared to be a stab wound, according to court documents.

Family members confirmed to MTN the aunt's name, Jonni Dreamer, and the grandmother's name, Deanne Dreamer.

Daniel Dreamer was sentenced Wednesday to two-and-a-half years in jail in tribal court, which is severely limited in its authority to hand down harsher punishments for crimes such as homicide.

Crow Tribal Prosecutor David Sibley confirmed to MTN News that the FBI is also investigating. Dreamer has not been charged in federal court, which carries harsher penalties than tribal court.