but as they get ready to remove rembrandt's only sea scape, a high-pitched alarm sounds.r steven kirkgen has investigated this case for the boston clo"boston globe" for de. abath told him the alarm was developed to keep visitors from getting too cross to the rem brandt. >> that sea scape, even if you look at prints of it now, images of it now, you will see an etching of rembrandt itself. odd experts, odd specialists, common folk knew that. they would come up and put their finger close to, point out the image of rembrandt. if they got too close, the alarm would sound. >> he says the thieves then smashed the alarm. >> that was really a compelling little detail to me because it seemed like that worked. that -- if you got too close, the sound would go off. as i went through the rest of the security that was in place at the museum, nothing else was there to guard the museum's valuables. >> like the motion detectors, this alarm was not connected to the outside world. but did the thieves know that as well? because they didn't pack up and leave. they continued on with their crime

making off with rembrandt's only sea scape. allen schauffler reports. >> it is an odd thing for a museum to be best known for the objects that are not there. but that's the case for boston's gardner mutually. two thieves stole 13 pieces mostly paintings and not just any paintings works by rembrandt ver vermeer degas monet. >> art crimes researcher erin thompson. >> in the history of the u.s., only 5% is returned. up to 20 to 25% of well-known works of art masterpieces are returned. >> linking the heist to organized crime even identifying suspects. but there have been no arrests. >> pieces that were taken were very eclectic and it's been difficult for us to determine the reasoning behind the paintings and the pieces that were taken. >> we're looking at the touch room of the museum, including from this frame rembrandt's christ in the storm in the sea of galilee. >> in fact what may be missing forever, you can always take this virtual tour, createon the 25th anniversary of the huge theft. >> why haven't these piece he resurfaced?