This can be difficult because the money is often funneled through other entities (as LPs to VC and growth funds, etc.)
I've had more than one VC tell me they couldn't guarantee that there was no Saudi money in their fund, even though they didn't have any direct KSA LPs.
I would hope we (Seam) are one of them. K, granted it's extremely hard to trace all the LPs of a fund; but at the very least we don't take calls with questionable funds/individuals. Once we've shipped our first product, I'll try to write down why, and propose a framework by which founders can better assess the money they're taking. NOT all money is green.
I've had more than one VC tell me they couldn't guarantee that there was no Saudi money in their fund, even though they didn't have any direct KSA LPs.