The property is enormously valuable AND its tangible.  They can grab it easily.  Who knows where Epstein's money is. As for evidence of crimes, they just executed a search warrant over the weekend and found what seems to be child porn.  AND the fact that they got a search warrant means they had some evidence of crimes beyond 2005, some new evidence led them to the warrant. Seizure of property is often used in federal cases.  It also would force him to live elsewhere if he ever got out after his conviction.