The captain locked out of the cockpit of the Germanwings plane that crashed in the French Alps used anaxeto try and force his way backin, German daily Bild said Friday, citing security sources.

Co-pilotAndreas Lubitz appeared to have deliberately flown the plane into the side of a remote mountain after locking the captain out of the cockpit, French officials have said, killing himself and all 149 others aboard Tuesday.

The cockpit flight recorder showed that the captain repeatedly knocked and tried to get back in as the plane went into its fatal descent, French prosecutors said. However, Bild reported that the captain also tried using anaxeto break down thecockpit'sarmoureddoor.

READ: Spain PM 'deeply shaken' by France air crash findings

This could not be immediately confirmed, but a spokesman for Germanwings confirmed to AFP that anaxewas on board the aircraft.

Such a tool is "part of the safety equipment of an A320," the spokesman told Bild.

READ: Precedents of pilots downing their planes