A bizarre nocturnal sound has left the residents of Forest Grove, Oregon, terrified.

According to The Oregonian, residents say the sound occurs at random intervals and can last “anywhere from 10 seconds to several minutes.”

“I’ve been woken up three or four times,” local resident Colleen Ahrens told KATU-TV. “It almost sounds like someone needs to change their brakes.”

Chester Epperson, who lives near Ahrens, joked to KATU that “Maybe ‘The X-Files’ back on TV again.”

“High-pitched, it’s got a pause. I’ll keep my ears out,” he said.

According to KATU, the source of the sound is still unknown. Officials have “ruled out gas lines, utility relief valves and fire alarms.”

“It’s definitely a horrendous noise,” Dave Nemeyer, the local fire marshal, told ABC News. “I have no idea what the noise is. [The resident] described to us that it was coming from the middle of the street. To me, it sounds like the sound of train tracks, that metal screeching sound, but there are no train tracks near her home … so that’s obviously ruled out.”

Tobin Cooley, an audio expert, told KATU that the sound is “baffling.”

“It sounds like some sort of pressurized gas or air through a fitting or valve or something,” he said. “It’s not steady state, and you can’t predict when it’s going to happen. Those are all interesting sound features.”

The community is still guessing the source of the sound.