ROTTERDAM, Netherlands Police hunting for the thieves who broke into a Rotterdam art gallery and snatched seven paintings worth millions are releasing security camera footage of the heist in a bid to gather more tips.
But don't expect to see the thieves' faces.
Detectives said in a statement Friday "the perpetrators are not recognizable in the images" but they hope members of the public may recognize the bags they were carrying.
Three dark, grainy stills posted on a police website show the thieves apparently walking out of the gallery's rear door.
The thieves broke into the Kunsthal gallery in Rotterdam early Tuesday morning and fled with paintings by artists including Pablo Picasso, Claude Monet and Henri Matisse.
Chris Marinello, director of The Art Loss Register, an organization that tracks stolen artwork, told "" that the high level of sophistication with which the crime was pulled off suggests the thieves had inside information.
"The police will be looking at friends and relatives of various museum personnel, looking into their backgrounds to see if they can find some kind of a connection," he said. "It just went too smoothly, this theft."
Roland Ekkers, spokesman for the Rotterdam Police Department, said, "The alarm system in the Kunsthal was supposed to be state-of-the-art, so we have got no reason to believe that it's not. But somehow the people responsible for this found a way in and a way out and they found time to take seven paintings."
Together, the paintings have an estimated value in the tens of millions of dollars, which would make this one of the biggest art heists in recent history. But Marinello says despite the high value carried by the art, the people who took it will have a hard time selling it.
"You take these to Vancouver, or Doha, you are not going to be able to sell them," Marinello said. "No respectable dealer or auction house is going to touch them."
Officials remain optimistic that the stolen artwork will soon be recovered.