A Hamas leader has disowned his son after the younger man claimed he spied for Israel.Hamas Web sites on Monday quoted a letter by Sheik Hassan Yousef disowning the son. Hamas said the letter was smuggled out of the Israeli prison where he is being held.The elder Yousef, who helped found the militant Islamic group two decades ago, was humiliated last year when his son Mosab announced he had converted to Christianity.Monday's announcement means the son loses his inheritance and the family will never speak to him — or about him — again.