A human leg has been found abandoned on a New York subway track, police said, sparking an investigation into who it once belonged to and how they lost it.

The NYPD said the leg was found at about 1 p.m. ET on Saturday in the Concourse neighborhood of the Bronx, between 167th Street and 170th Street, on the line of the 4 train, according to a statement given to NBC 4 New York.

No details were released about the leg, such as whether it appears to be from a male or female, nor the possible age of its owner.

New York’s medical examiner is now examining the leg to find out more details and potentially solve the mystery.

Thousands of items are lost across the city’s sprawling transport network every month, including all manner of more common things such a funeral urns, a welder’s mask and a blender.

The 4 train service was shut down as a result on Saturday but later restarted later Saturday afternoon, NBC New York reported.