A truck ferrying 28 artworks worth $6.5 million that included pieces by Picasso, Fernando Botero, and Spanish sculptor Eduardo Chillada was stolen over the weekend from a warehouse in the Spanish town of Getafe, just south of Madrid. Footage from security cameras shows three hooded men making off with the vehicle, the keys to which had been left inside the glove compartment, according to the Associated Press. The art was being transported back to the six galleries in Madrid, Barcelona, and Cologne, from which they had been on loan for an exhibition in Germany.

A police statement describes how an alarm alerted officers that the door to the warehouse had been forcibly opened. By the time authorities arrived, however, the truck was gone. Last Tuesday, the vehicle — owned by Spanish transport company Crisóstomo — was found abandoned and emptied of its art cargo in the southern town of Alcorcon.

Representatives of the galleries, which included Stefan Röpke gallery in Cologne and Juan Gris gallery in Madrid, have been ordered by authorities not to discuss the case or publicize the identity of the specific missing works, for fear such information might impede the investigation of the art theft special unit. However, the art dealers continue to speculate to the press. "It has all the hallmarks of an inside job," the director of Stefan Röpke told the Telegraph.

Besides the Picasso drawing and the Botero and Chillida pieces, missing works include lithographs, sculptures, and paintings by Spanish artists Gonzalo Gonzalez, Julio Gonzalez, and Antonio Saura, as well as Slovenian artist Cveto Marsic. Several of these artworks were not insured."Nothing like this has happened to us in 40 years," David Fernández, of the Juan Gris gallery, told the Guardian. "At a bad time like this some galleries are not insuring their work, which is mad. It never happens until it happens."

As of yet, no arrests have been made, and Fox News reports that the only person questioned in the case has been the Romanian truck driver whose vehicle was stolen. And the outlook is bleak: only around 15 percent of stolen artworks are recovered, according to one policeman assigned to the case. The officer told the Telegraph that art theft had become the third largest black market trade, following drugs and arms trafficking.