Updated

FBI bomb technicians are currently in the process of clearing the Oregon wildlife refuge of possible traps or explosives that protesters may have been left behind after the last holdouts left Thursday, a law enforcement source close to the investigation tells Fox News.

Fox is told that authorities had reason to suspect hazardous traps may have been left behind after hearing chatter from some of the protestors there. That chatter came via a livestream of the standoff broadcast hours before the remaining four protestors surrendered.

The concern over possible booby traps at the scene was first reported by Reuters last night.

This source tells Fox News the FBI always exercises caution when working a crime scene, but particular emphasis is being placed on sweeping the Malheur National Wildlife Refuge in light of that chatter.

Fox is told FBI bomb technicians began the methodical process of clearing the scene Friday morning and that the activity is expected to last at least the majority of the day. Once cleared, FBI's Evidence Response Team will move in and begin the evidence collection process.

This source tells Fox that at this time bomb techs have not found anything at the scene that is cause for alarm.

The last four protestors occupying the wildlife refuge in eastern Oregon surrendered to FBI yesterday and are now in federal custody.