Police said thieves knew where to cut a hole in the Brussels Airport security fence, that there would be valuable cargo and when the airplane would be most vulnerable during its takeoff routine, Britain's The Daily Telegraph reported Wednesday.
It took thieves less than 3 minutes to steal about $50 million in diamonds from the cargo hold of Helvetica Airways flight LX789 Monday, officials said.
Two vehicles outfitted with blue flashing lights and carrying eight men disguised as police officers drove through a security fence and onto a tarmac in the heist. Although the pilot, co-pilot and several other people were held at gunpoint, no weapons were fired and no one was injured.
"There is a gap of only a few minutes," said Caroline De Wolf, a spokeswoman for the Antwerp World Diamond Center, where the shipment originated. "The people who did this knew there was going to be this gap and when."
Police said they believe the robbers had military training because of the "iron discipline" exhibited during the operation.
FlandersNews.ne reported police recovered a burned-out delivery van in Zellik in Flemish Brabant province. Detectives were examining the vehicle to determine whether it was used in the robbery.
The airline said it would wait for the completion of the police investigation before commenting.