The feds were there because the home was targeted by burglars last month, and they believe the thieves may have been after the stunning 45-carat Marlborough diamond, which was stolen in a brazen London heist in 1980, the Chicago Sun-Times reports.
Chicago mobsters Joseph “Jerry” Scalise and Arthur "The Genius" Rachel were convicted of the jewel theft and served time, but the diamond, valued at nearly $1 million, has never been recovered.
Scalise was arrested again in early April after authorities said he and three men were casing LaPietra's home. Feds may believe the diamond is hidden there, despite reports that the gem was cut up and sold long ago.
It's not clear if the agents were executing a search warrant or if the home's current owner, LaPietra's daughter, game them permission.