British police say they are investigating the possibility that a man found dead on a roof in west London had been a stowaway on a flight that was on approach to Heathrow Airport.

Authorities say they found a second man in the undercarriage of a plane from Johannesburg after it landed. The second person, who is between 25 and 30, was taken to a west London hospital and is in serious condition. Police say there is no evidence to link the two, but that it is a line of inquiry.

Police say the first man was found Thursday on a roof in Richmond, which is below the flight path.

British Airways said Friday it is working with police in London and Johannesburg to establish the facts in this "rare case."