MANITOWOC, Wis. (AP) — Authorities say a caller who phoned in a bomb threat to a Wisconsin county sheriff's office made an apparent reference to "getting justice" for the man at the center of the "Making a Murderer" documentary.

A statement from the Manitowoc Police Department says a male caller made the threat around 6:40 p.m. Wednesday. It says the caller described bombs inside the Manitowoc County sheriff's office building and a vehicle outside with explosives.

The statement says the caller mentioned "getting justice for Steven," what it describes as an apparent reference to Steven Avery, the Wisconsin man whose prosecution in a 2005 killing was the centerpiece of the Netflix series. The series questions Avery's treatment and suggests the possibility Manitowoc County sheriff's deputies planted evidence.

Authorities deemed the area all clear; they found no suspicious devices.

An investigation is ongoing.