Can I sue the scammer if I find out who they are?

Technically yes; practically, it depends on the country. Suing requires (a) jurisdiction over the defendant, (b) ability to serve process, (c) enforceable judgment, and (d) traceable assets to enforce against.

For scammers based in cooperative jurisdictions (UK, EU, US, Canada, Australia, Singapore) — yes, civil suits and asset-freezing orders are viable. For scammers based in jurisdictions with no MLAT relationship, no extradition, or controlled judicial systems — judgments are essentially symbolic.

Before investing in litigation, get a realistic enforcement assessment from a lawyer in the scammer's jurisdiction, not just yours. A $200 second opinion can save $50k in fruitless legal fees.