Only because you asked about "sabotaging", If they already entered the USA, then maybe a well crafted letter (better to ask an Attorney to do it) to USCIS to make their future N-400 citizenship application more challenging, and who knows given how aggressive and the quotas that ICE has, maybe a letter to them too. But if they haven't entered USA yet, maybe do a shotgun approach to notify CBP, USCIS, NVC, embassy, and maybe your congressman (to tip off CBP in addition to for you) ASAP in hopes that something might stick. Maybe even ICE.
But as others have said, its difficult to do much if they already entered the USA .. but it won't hurt to give the above a shot ..
And contact a good divorce attorney!