Yellowstone National Park managers have located some of the dozens of bison that were illegally released from a quarantine area on Tuesday, according to a news release Thursday.

Meanwhile, the criminal investigation continues into their release from the Stephens Creek facility where 24 bulls were held in one pen since March 2016 and 28 were held since March 2017.

"Investigators working on this case have confirmed that bison were intentionally released by unknown individuals when pens were broken into and damage occurred to government property," according to the news release.
Some of the 52 bison have been located in the Mammoth area, but the news release did not say if any of them were captured.

Park staff will continue to monitor bison movements, and they will attempt to capture  any that return to the Stephens Creek area.

The bison were being held and tested for brucellosis at Stephens Creek facility, which is permanently closed to the public, as part of a plan being considered to establish a quarantine program to augment or establish new conservation and cultural herds of disease-free plains bison.

The program also would enhance cultural and nutritional opportunities for Native Americans, specifically for the Fort Peck Tribes in Poplar, Mont.; reduce the shipment of Yellowstone bison to meat processing facilities; and conserve a viable, wild population of Yellowstone bison.

Brucellosis is a bacteria-caused, contagious disease that primarily affects cattle, bison and other ruminant animals. It also affects humans. Brucellosis can cause cattle to abort. In humans, it is known as undulant fever because of the severe intermittent fever, accompanying infection, according to the U.S. Department of Health's Animal, Plant and Health Inspection Service.

Anyone with information about this incident is encouraged to call the Yellowstone National Park Tip Line at (307) 344-2132 or email