An eerie flute-like sound is driving citizens of one Oregon town bananas.

Aliens, ghosts and leaking gas pipes have all been touted as possible explanations for the high-pitched, whistle-like note heard at random times in Forest Grove over the past few weeks. But residents can't figure out where it's coming from, and experts are equally stumped.

Here's what it sounds like:

Mystery sound frustrates people in a west Forest Grove neighborhood. Where it could be coming from? #LiveOnK2 @ 11pm pic.twitter.com/p0inj5TBr2 — Chris Liedle (@chrisliedle) February 16, 2016

The noise strikes at all times of the day and night, and lasts from 10 seconds to several minutes.

"I've been woken up three or four times," local resident Colleen Ahrens told KATU. "It almost sounds like someone needs to change their brakes."

Fire, police and public works officials have investigated the noise that's plaguing the community of 22,500, about 25 miles west of Portland, but to no avail.

Forest Grove Police Capt. Mike Herbs said if someone was making the noise on purpose, then it was a city ordinance violation.

"At this point, we don't have information that would lead us to believe that's the case," Herbs told The Washington Post.

He added that some people thought the sound could be "an alien mother ship or a warning sign of something to come."

Hemera Technologies via Getty Images The mysterious noise sometimes sounds likes it being played on a flute.

Melissa Moore, a spokeswoman for Northwest Natural Gas, ruled out a leaking gas line or relief valve.

A spokesperson for Forest Grove Fire and Rescue said it was business as usual, although firefighters are collecting information about the sound.

"We aren't waiting for it to make a noise. We are going about our duties," the spokesperson said.

ADAM GAULT/SPL via Getty Images Leaking gas lines or relief valves have been ruled out as a possible cause.

Audio engineer Tobin Cooley, president of Listen Acoustics, was drafted by Reuters to assess the phenomenon and he said its high pitch and ambiguous point of origin was "unusual."

"Higher frequencies like this tone are very directional sounds versus low-frequency sounds which can seem to come from anywhere or everywhere at once," Cooley said, stressing that he only listened to poor-quality recordings.

"What surprises me is that neighbors have not been able to locate where this is coming from," he added.

It's not the first time Forest Grove has been hit by such a sensation. Former residents reported hearing similar sounds echoing through the night several decades ago. However, the cause was not solved back then either.

The truth of the sound must be out there. Now it just needs to be found.

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