A sharp, high-pitched ringing noise has residents of a suburban Oregon community baffled.
Residents of Forest Grove say they’ve heard the noise for weeks and at all times throughout the day, according to Fox 8.
One resident of the town, 25 miles outside Portland, recently recorded the sound and posted it on social media, the station reported.
A woman told KATU-TV the other day the noise has interrupted her sleep three or four times in the past three weeks.
“It sounds like brakes to me, the cyclical, you know, screeching of … you need to change your brakes,” Colleen Ahrens told the station.
Chester Epperson had the opinion the noise was coming from a boat.
“Maybe the X-Files [are] back on TV again,” he joked.
Officials have ruled out gas lines, utility relief valves and fire alarms, the station reported.
Audio expert Tobin Cooley wasn't able to solve the mystery after listening to the recording and conducting measurements, KATU reported Saturday.
"It sounds like some sort of pressurized gas or air through a fitting or valve or something," Cooley said. "It's not steady state and you can't predict when it's going to happen. Those are all interesting sound features."
Cooley said he thought the sound was nearby as high-pitched tones don’t travel very far.