No one has pointed out that pilot credentials can be stolen; see the link below. If no one knew this copilot by sight, perhaps he was killed and his credentials used by a terrorist.
Co-pilot lived with parents, keeping a flat in Duesseldorf.
I read his parents have been questioned, and police have Montabaur under guard.
“No one has pointed out that pilot credentials can be stolen; see the link below. If no one knew this copilot by sight, perhaps he was killed and his credentials used by a terrorist.”
I was speculating along these lines as well. Did Lubitz fly with this particular crew before?