The co-pilot of the Germanwings plane which crashed in the French Alps in March may have practised a rapid descent on a previous flight, a report by French investigators has said, the BBC reports.

The report said Andreas Lubitz repeatedly set the plane into an unauthorised descent earlier that day.

Lubitz is suspected of deliberately crashing the Airbus 320, killing all 150 people on board.

The plane had been flying from Barcelona to Duesseldorf on 24 March.

The descent occurred on the plane’s outbound flight from Duesseldorf to Barcelona on the same day, the report said.

The co-pilot is known to have suffered depression in the past.

Last month German prosecutors revealed that Lubitz had researched suicide methods and the security of cockpit doors.

Voice recorder findings suggest he locked the pilot out of the cockpit on the doomed flight.