For 30 years, Garfield novelty phones kept washing up on the beach in Brest, France.

No one knew why.

An environmental group recently set out to solve the case.

A farmer said that the phones may have fallen off a shipping boat in the 1980s and into a nearby sea cave.

By golly! He was right.

For nearly 30 years, it remained a mystery.

In varying quantities and qualities, Garfield corded phones had been washing up on the shores of Brest, a port city in Northwest France. For years, residents couldn't trace where the phones were coming from — or why. They just knew they were coming TO A 15-mile portion of the beach. Ceaselessly. Without rhyme or reason.

"It never stops,” Claire Simonin Le Meur, who lives in the area, told The Local.

The phones have big eyes that open and close when the phone is lifted off its cradle. They don't float. In 2018, 200 phones washed up.

"At each [beach] clean, we collect three or four telephones, either complete or in pieces,” Le Meur, who organizes beach litter sweeps, said.

The phones have been washing up since the 1980s. FRED TANNEAU/AFP/Getty Images

But now there might be an end to the phones. Recently, officials were able to trace the Garfields to their source.

An environmental group called Ar Vilantsou led the charge, with frequent call-outs on social media. Their posts jogged the memory of a local farmer who first recalled spotting a Garfield on the beach after a particularly rough storm in the 1980s.

Read more: A rat defeated a rattlesnake with a soaring 'ninja-style' kick to the head

One thing led to another, and the farmer remembered that the phones had blown off a boat and had landed in a sea cave.

His theory appears to be correct. A crate of the phones was found in a sea cave not far off the coast. Remarkable.

Although the container has been located it cannot be moved due to the way it has settled into the cave. So while the case of the Garfield phones is effectively closed, their remnants will continue to wash ashore.

That said, Paws, the company that currently licenses Garfield, told France Info couldn't verify the decades-old tale of the shipping boat. It's also worth noting that the phones are currently for sale on eBay, where they cost about $40 a pop depending on the seller.

After all, the authentic French phones might have a touch of water damage.