SYDNEY, Australia (AP) - Osama bin Laden's terror network claims to have bought ready-made nuclear weapons on a Central Asian black market, the biographer of al-Qaida's No.2 leader was quoted telling an Australian television station. In an interview scheduled to be televised Monday, Pakistani journalist Hamid Mir said Ayman al-Zawahri claimed "smart briefcase bombs" are available on the black market. It was not clear when the interview between Mir and al-Zawahri took place. U.S. intelligence agencies have long believed al-Qaida attempted to acquire a nuclear device on the black market but said there is no evidence they ever succeeded....