Someone keeps stealing urinal drain grates in Japan that cost less than $5 each, and the police can't figure out why

• A spate of urinal drain grate thefts has struck the Japanese city of Sapporo.
• At least 38 drain covers have been pinched by an unknown thief, local media reported.

The police in Sapporo, Japan, are baffled by a mysterious string of thefts involving urinal drain covers.

At least 38 drain grates from 16 public bathrooms went missing from May 16 to 30, reported national paper Yomiuri Shimbun, citing city officials.

Some of the grates were replaced on June 1, but the lids, which cover drain holes in urinals, started disappearing again a week later, the outlet reported. Even the toddlers' urinals in women's toilets weren't spared, Yomiuri Shimbun reported.

Several key patterns in the thefts have emerged. The bathrooms were all located close to Sapporo's Okadama Airport, and the thefts occurred on weekdays, per Yomiuri Shimbun.

But authorities have no idea why anyone would want to pilfer urinal drain grates. The price of one lid is around $4.80, Asahi Shimbun reported.

"Why are you stealing this?" a city official wondered aloud when speaking to the Asahi Shimbun.

Police are investigating the disappearances as a theft, and have sent officers to patrol the area, Yomiuri Shimbun reported.

The public bathrooms — being bathrooms — didn't have security cameras, so investigators will have to rely on footage taken nearby, per the outlet.

Residents told the outlet they're frustrated by the thefts.

"I don't understand the reason at all. Please stop doing this at the public restroom," said a 69-year-old man in Higashi Ward, per Yomiuri Shimbun.

Meanwhile, police in the city of Toyota in Aichi prefecture were in May searching for someone who stole a flushing handle from a toilet, rendering it unusable.

And in 2021, a 26-year-old office worker in Funabashi city was arrested on charges of stealing entire toilet bowls from houses to sell at second-hand stores.

The Sapporo police department did not immediately respond to a request for comment sent by Insider.