The FBI knows who pulled off the biggest art heist in history, but they aren't naming names. And as for what become of the $580 million worth of masterpieces stolen exactly 23 years ago from a Boston museum, investigators say that trail went cold a decade ago.

The FBI said Monday it would be "imprudent" to disclose the identities of the thieves who stole 13 works of art from Boston's Isabella Stewart Gardner Museum in 1990, but said they belong to a criminal organization, and they said they believe the art work has "changed hands several times" over the years....