Something happened on Thursday that, unfortunately, isn't entirely unheard of in London: A body was found early that morning, and police suspect the man might have fallen from a plane.

Authorities are investigating whether the man stowed away on a British Airways flight that went over the area on its way from Johannesburg to London's Heathrow Airport.

When the flight landed, another man was found in the plane's undercarriage and was said to be in critical condition. The Associated Press reports that authorities are trying to determine whether both men might have been hiding on that plane, noting that there is no evidence to link the two cases.

The Guardian quotes a British Airways spokeswoman as saying, "We are working with the Metropolitan police and the authorities in Johannesburg to establish the facts surrounding this very rare case."

The newspaper says the body was found on the roof of an office building in the Richmond district in southwest London about an hour after the flight landed:

"It is not clear if he was killed in the fall; flight data reveals the plane would have been at an altitude of around 1,400ft (427m) when it passed over the area."

Richmond is only about seven miles away from Heathrow.

Reuters notedthat other bodies have been found in the Richmond and Kew districts, which are on a point in the flight path at which many planes open their landing gear doors as they approach the airport.

In 2013, some of you may remember, a Mozambican man named José Matada fell from a plane that was also flying over London. According to the BBC, the 26-year-old had stowed away on a flight from Luanda, Angola.

NPR's Mark Memmott wrote about stowaways last year when a 16-year-old boy from California sneaked onto a flight from San Jose to Hawaii by hiding in a wheel well. Mark said that while it's possible for people to survive a flightin a jet's wheel well, they probably won't:

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