Allegheny County police are investigating an apparent signal hijacker who has used Pittsburgh public safety radio channels to broadcast hateful messages and threats.

The messages, all of which appear to have been pre-recorded, feature Nazi propaganda, refer to the conflict in Iran, make threats against Pittsburgh Mayor Corey O’Connor, and celebrate the 2018 mass shooting at the Tree of Life Synagogue in Squirrel Hill. The messages appear to have begun mid-afternoon Monday, and continued intermittently through mid-afternoon Tuesday.

The messages appear to have been broadcast on frequencies used by city police in Zones 3 and 6.

Officials with Allegheny County, which oversees the emergency radio system used by police, said in a statement that the system was “not hacked,” and that an “unknown user” accessed the analog radio system to transmit the messages.

County police safety spokesperson Jim Madalinsky said the Allegheny County Police and the FCC are assisting Allegheny County Emergency Services in investigating the incidents, and declined further comment because the investigation is active. He confirmed that public safety officials who typically use the radio channel have temporarily been moved to a secure channel, and said emergency operations and responses have not been impacted.

“This situation has happened in the past, and we take these matters seriously,” a statement from Allegheny County Emergency Services said. “We are working closely with our law enforcement partners, and this remains an active and ongoing investigation.”

Pittsburgh public safety spokesperson Cara Cruz confirmed to WESA that the origin of the radio traffic is not a lost, stolen or missing City of Pittsburgh Public Safety Radio. Mayor Corey O’Connor’s office declined to comment.