Investigators from the federal ATF and state Fire Marshal’s Office are still working at the scene of the Robbins Lumber fire and explosion in Searsmont

A news release Thursday evening said their latest efforts have focused on interviews as well as digging up and recovering evidence.

Investigators say they have now sifted through hundreds of cubic yards of sawdust and debris in an extremely labor-intensive operation.

Two cranes are also being used at the silo locations. Investigators say crews spent the day Thursday conducting preparatory work and evaluating site safety ahead of a digging operation with the cranes.

Fire investigators say they hope to wrap up the on-scene portion of the investigation in the coming days.

They say investigative personnel attended the memorial Thursday evening honoring Morrill Firefighter Andrew Cross, who died in the fire and explosion.