The black box recovered from the wreckage of a plane crash that killed Brazilian socialist presidential candidate Eduardo Campos failed to record his flight, the air force has said.
The two hours of recordings it contained were not related to Wednesday's doomed flight.
This is according to the military branch in charge of the crash investigation.
Mr Campos, 49, died when his campaign jet slammed into houses in Santos city in bad weather.
The crash resulted in all seven people on board being killed and setting buildings alight.
He had been running third in opinion polls for the October election.
A popular former governor of the north eastern state of Pernambuco, Mr Campos was married with five children.
His remains are due to be buried in the coming days in Recife, capital of Pernambuco.