Food delivery workers in New York City have long been preyed upon by muggers, but with the advent of app-based ordering, many thought they would be less of a target because they usually don’t carry as much cash.

In recent months, though, they have fallen victim to a new crime wave: theft of their electric bicycles, which are propelled by batteries and can cost as much as $2,000.

Nearly two dozen workers have been attacked, according to the Police Department. The e-bikes were stolen by the same two men, the police said, who ambushed the riders with pepper spray or at knife point. There have been no arrests.

In recent days, two more e-bikes were stolen, though it is not clear whether these thefts are related to the 22 others.