The four Boeing workers killed when a Turkish Airlines plane crashed shortly before landing at Schiphol airport at the end of February were carrying top secret information about an advanced US radar system, the Telegraaf reports on Friday.

The paper says laptops containing the secret plans were removed from the aircraft shortly after the crash.
The four Boeing staffers were working on a US defence department contract to develop a special airborne radar system known as Peace Eagle for the Turkish airforce, the paper says.
The Peace Eagle is a Boeing 737-700 fitted with the latest radar technology to act as an airborne early warning and control AEW&C aircraft.
Wrong hands
Several hours after the crash, Boeing security officials asked the US embassy in The Hague to remove the computers from the plane to stop them falling into the wrong hands, the paper claims.
According to ‘extremely confidential sources’ FBI agents then flew in from Frankfurt by private jet to take control of the laptops.
The paper says the public prosecution department in Haarlem has confirmed that the laptops which contained ‘confidential military information’ were removed from the plane. However, a spokeswoman said no US officials were involved.