New technology is raising hopes for the recovery of the 13 masterpieces stolen from Boston's Isabella Stewart Gardner Museum 25 years ago.

Law enforcement officials released a surveillance video last week showing a security guard, allegedly unauthorized, letting an unknown man into the museum 24 hours before the heist.

Never before seen by the public, the footage, along with materials from the crime scene, can now be used for facial recognition, video enhancement, and fingerprint and DNA analysis. Since the video was released, some 40 tips have come in.