BUTLER, Pa. -- The FBI's Joint Terrorism Task Force is investigating the deaths of 400 minks at a Butler County farm.

Authorities said someone released 2,800 minks at the Oakwood Mink Farm in Marion Township out of their pens late Tuesday night or early Wednesday morning.

Officials said 300 baby minks and 100 nursing minks died.

The farm owners said their two dogs were also shot.

The owners of the farm are not commenting. But Teresa Platt, executive director of Fur Commission USA, which represents mink farmers in 28 states, told the Butler Eagle that investigators are trying to determine if militant animal rights activists or other domestic terrorists are behind the attack.

Pittsburgh's FBI spokesman Bill Crowley confirmed the investigation, but he won't say why it's being handled by the terrorism task force.

Get the latest details on the investigation on Channel 11 News.