The founder of the popular messenger service WhatsApp Jan Koum has recently made a $2 million donation to the American Israel Public Affairs Committee (AIPAC), its largest donation to date. The California-based billionaire, who normally leads a recluse life, has come into the spotlight recently with his large donation, leading to scrutiny over his other past donations. Koum, a 46-year-old retired entrepreneur who made his fortune from his invention of WhatsApp and then its sale to Facebook, immigrated as a teenager from Ukraine with his mother to northern California, where he learned computer …