The CIA has concluded that members of Al-Qaida and allies of Pakistani tribal leader Baitullah Mehsud were responsible for last month's assassination of former Pakistani prime minister Benazir Bhutto, The Washington Post revealed on Friday. The terror group was also behind a new wave of violence threatening Pakistan's stability, CIA director Michael V. Hayden, said in an interview. In the most definitive public assessment by a US intelligence official, Hayden said Bhutto was killed by fighters allied with Mehsud, a tribal leader in northwestern Pakistan, working with the support of al-Qaida's terrorist network. The CIA's findings are in accord with the Pakistani government's assertions made shortly after the assassination. The alliance between local and international terrorists poses a grave risk also to President Pervez Musharraf's government, a close US ally in the war on terrorism, Hayden said in 45-minute interview with the paper. "What you see is, I think, a change in the character of what's going on there," he said. "You've got this nexus now that probably was always there in latency but is now active: a nexus between al-Qaida and various extremist and separatist groups."