For years, the rusty metal box lay entangled in poison ivy and trees in a Staten Island backyard. The homeowners thought it was just an electricity box. But last month they were amazed to discover it was instead a locked safe that held money and jewels that they traced to a $52,000 robbery in 2011.

And so began the tale of Bamboo Bob, the Ninja Burglar and the stolen treasure of Staten Island.

“It is like a childhood dream that you find treasure,” said the homeowner, Matthew Emanuel, who eventually tracked down the safe’s owners. “I knew it was quite a find.”

Mr. Emanuel, a financial adviser for Bernard Herold & Company, and his family moved in to their house in the Todt Hill neighborhood about four years ago. From the deck and the couch in their family room, they could see the metal box on the edge of the property, but rarely paid attention to it. “It was just a rusty box,” he said. “Behind some trees.”

In the spring, after winter storms and hungry deer ravaged their arborvitae trees and other vegetation, Mr. Emanuel called in a horticulturist who specializes in exotic plants to help them plant bamboo on the side of the yard for more privacy.