One body has been seen in the underwater wreckage of the plane that was carrying footballer Emiliano Sala and pilot David Ibbotson.
A search on Sunday found the Piper Malibu plane on the seabed off Guernsey, almost two weeks after it went missing.
The Air Accident Investigation Branch (AAIB) confirmed the sighting on Monday morning.
It added it was now considering the next steps.
The "substantial amount of wreckage" of the plane, which went missing on 21 January, was found on Sunday morning after a privately-funded search was started.
The flight was carrying Argentine striker Sala and pilot David Ibbotson from Nantes, north west France, to Cardiff after Sala completed his £15m move to Cardiff City.
In a statement the AAIB said: "The remotely operated vehicle (ROV) carried out a further search of the area overnight, but did not identify any additional pieces of wreckage.
"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."
Oceanographer and marine scientist David Mearns confirmed the wreckage had been found on Sunday after "a couple of hours" of searching the seabed.
An online appeal started by Sala's agent had raised £324,000 (371,000 euros) for the private search, which Mr Mearns offered to help with.
Working jointly with the AAIB, Mr Mearns's ship and another search vessel, the Geo Ocean III, began combing a four square mile area of the channel, 24 nautical miles north of Guernsey.
The AAIB ship remained in place, sending down a remotely controlled submersible overnight, which captured the footage of the wreckage.