"Based on analysis of ROV (underwater remotely operated vehicle) video footage, the AAIB investigators on board the vessel concluded that the object is wreckage from the missing Piper Malibu aircraft," Britain's Air Accidents Investigation Branch said in a statement.
"Tragically, in video footage from the ROV, one occupant is visible amidst the wreckage.
"The AAIB is now considering the next steps, in consultation with the families of the pilot and passenger, and the police."