For days, Seattle writer and attorney Nathan Barnes has been consumed by a strange mystery: Who is broadcasting the same 20-song playlist over and over via FM radio? There are no call signs, no ad breaks, no DJ or explanation... just the same odd 59-minute playlist, cycling 24 hours a day. What?

Because we are all stuck inside, observing doom, this is exactly the kind of bonkers mystery that Twitter needs. After posting about the strange broadcast, Nathan's followers leapt into action, digging into radio records, driving around town with car radios carefully tuned, and wandering through Cal Anderson park looking for answers.

"We have a five-year-old and we’re often on the classical station during the day, especially a few weeks ago when you’re trying to be wholesome and haven’t given up yet," Barnes said in an interview with The Stranger.

The mystery began when someone, him or his wife, accidentally bumped the dial from 98.1 over to 98.5, heard some pleasantly nostalgic classic rock, and left it there. A few hours later, they observed, "I swear I've heard this song before."

The playlist starts every time with Jim Croce singing Time in a Bottle. Then it's Signs by the Five Man Electrical Band. Then Killer Queen by Queen, Mr. Tambourine Man by The Byrds, Mercy Mercy Me by Marvin Gaye ... and so on. Good songs! But why play them together, Nathan wondered? He started writing down the tunes as they played, puzzling over them.

"I'm writing down the tracks like oh my gosh this must mean something," he recalls. "I was obsessing over it and eventually I had to get it out on Twitter."

A post on Tuesday immediately attracted attention, and amateur sleuths joined in. Some people analyzed the years in which the songs came out — no pattern. Others ran their initials through cypher keys — nothing.

Someone suggested looking for patterns in the time signatures. Someone else translated the years into binary. Another theory is that someone couldn't be near a loved one in the hospital, so they (somehow) broadcast the playlist of their favorite songs so they could feel close.

My guess was a community college radio project that someone forgot to turn off before the lockdown. My partner thought it was a service for retail stores to play over the speakers.

Everyone was thrown into a tizzy when the station unexpectedly broadcast a government PSA about getting a flu shot, then went back to the playlist.

Folks began chiming in with their location so they could triangulate the source, and Nathan kept his ear to the dial when he had to run an errand in Eastlake.

"I had convinced myself this was some kind of pirate radio station, someone in SODO who was pumping this out, just based on my drive," Nathan says.

The enigma was a welcome break from ... you know, everything else.

"Of course we’re all sitting around the house, everyone’s job is up in the air, businesses are closing, there’s a lot of anxiety," he says. "Thousands of people are now putting some amount of minor mental effort to shoehorn meaning into twenty songs picked at random by some software."

Wait, what? Picked at random by some software? Yes, as it turns out, the mystery has been solved and it meant ... nothing.

By Thursday, Nathan's Twitter thread had come to the attention of James Dalke, who owns the transmitter. A former Coast Guard radio engineer, he bought the station in a fire sale from a Christian broadcaster for $3,000, and set up a little automated box that plays songs at random. At some point — nobody's quite sure when — it glitched and got stuck on a loop.

One of Nathan's followers happened to know Dalke and gave him a heads up about the investigation, at which point Dalke "gave the box a kick," as Nathan describes it, and the playlist that had come to be known as "The 20" is no longer looping.

"Now I’m gonna have to find something new," Nathan says. "I don’t have anything to obsess about." He just finished writing a book — a guide to wildflower hikes that'll be out next year from the wonderful Mountaineers Books.

"When I turned that in to the publisher, all that I was left with was The 20," Nathan says, sounding a bit forlorn that the thrill of the hunt has ended.

So ... anyone got any local mysteries you need solved?