The trouble with current international anti-corruption laws is manifold
1. Requires that charges be instituted by affected state. This should be changed to allow individuals, NGO's, etc
2. No proper law covers international jurisdictions for economic crimes unlike human rights abuses. A Geneva Convention on corruption would be useful such that it does not rely on bipartisan agreements
3. Western powers are not obliged to monitor/capture illegal cashflows & assets. The convention in 2 above would oblige signatories to act
Am sure NSA, MI6, Mossad, etc know all about African and Russian thieves but do not care about them especially as the money ends up in their economies. That's how they are able to capture terrorists, enforce sanctions, what not.
Bottomline - no political will to tackle international graft