A man rides a horse at the occupied Malheur National Wildlife Refuge, on the sixth day of the occupation of the federal building, in Burns, Oregon, Jan. 7, 2016.
Rob Kerry—AFP/Getty Images
February 18, 2016 7:11 AM EST

Investigators gathering evidence at the site of an Oregon wildlife refuge that was occupied by armed protesters have found firearms, explosives and trenches dug in land that could contain Native American artifacts, federal prosecutors said. One of the trenches contained human waste.

The FBI is also concerned that some of the buildings or vehicles at the Malheur National Wildlife Refuge may be booby-trapped, prosecutors said in court documents filed Tuesday.

The documents do not say why the FBI is concerned about traps, but gives no indication any devices were found…

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