jt-041214-21.html WASHINGTON (JTA) – The FBI is investigating the mysterious death of a young American Jewish terrorism expert who worked at a think tank where research into Islamic extremism has drawn death threats, family and friends said. Jason Korsower, 29, died in his sleep at his father’s Atlanta home on Nov. 26, after Thanksgiving celebrations with his family. For his 29 years, Korsower had lived a full life, thriving in a Jewish youth group, serving in the Israeli army in a crack infantry unit, studying religion and most recently plunging into terrorism research in Washington. He was about to start...