No arrests have been made in connection with last month's shooting near Ignacio that left two people injured, according to U.S. attorney spokesman Jeff Dorschner.
Dorschner said the investigation is ongoing, and declined to identify any suspects.
The La Plata County Sheriff's Office said the shooting, which occurred within the boundaries of the Southern Ute Indian reservation, was reported about 8:30 p.m. Dec. 28 by employees at Mercy Regional Medical Center, where the victims were dropped off with gunshot wounds.
Lindsay Box, communications specialist for the tribe, declined to identify the victims but said they are non-native. They have since been treated and released from Mercy.
The tribe also declined to disclose details of the event, including a possible motive.
The FBI, Southern Ute Police Department and La Plata County Sheriff's Office are working the case together, Box said.
Despite no arrests having been made, Box said there is no concern for public safety.