TOKYO >> An elderly man took a backpack containing 60 million yen ($550,000) to the Yokosuka city hall in Kanagawa Prefecture.

It turned out to be an anonymous donation.

According to the city, the man, who appeared to be in his 70s or 80s, handed the backpack to a city worker on May 17 near the mayor’s office on the third floor of the city hall.

“There’s a letter inside,” the man told the worker. “You’ll understand when you see it.”

After he left, the worker opened the backpack and found 12 wrapped packs of 5 million yen. Each pack contained five bundles of 1 million yen, wrapped with a paper band from a bank.

Also in the backpack was a letter saying: “These are my savings I started when I was a first-grader. Please use it for something. I will donate it.”

The letter clearly stated his wish for anonymity, and the city will treat the money as a donation.

“I am so surprised and grateful that I don’t know what to say,” said Yokosuka Mayor Katsuaki Kamiji. “I will think carefully about how the money should be used.”