Was It Al Qaeda?

U.S. experts believe that Islamic jihadists with possible connections to Al Qaeda are the most likely perpetrators behind Thursday's assassination of Pakistani opposition leader Benazir Bhutto. But counter-terrorism officials warn that U.S. agencies believe it is still to early to pin the blame for the attack on any particular extremist group or faction.

Pakistan's government, led by long-time Bhutto antagonist (and Pakistani President) Pervez Musharraf, has already begun to accuse one specific Islamic militant leader of complicity in the assassination. On Friday, Pakistan's Interior Minister Hamid Nawaz claimed that his government had acquired an ''intelligence intercept'' in which Baitullah Mehsud, an alleged Al Qaeda leader based inside Pakistan, ''congratulated his people for carrying out this cowardly act.''

According to a purported transcript of the intercept reported by the Associated Press, Mehsud was in contact with an associate who described how "our men" had been present at the assassination. Mehsud supposedly replied: "It was a spectacular job. They were very brave boys who killed her."

Two U.S. counter-terrorism officials, who asked for anonymity when discussing the ongoing investigation, said that U.S. agencies so far had no hard evidence to confirm the authenticity of the purported Pakistani intercept. Likewise, the officials said, there is no hard evidence to confirm the role of Mehsud or any other particular Jihadist leader--or any particular Jihadist group or faction--in the Bhutto attack.

By the same token, the officials said, U.S. experts believe that the assassination bears the hallmarks of an attack by jihadists of some kind. The officials noted that both before and after Bhutto's recent return to Pakistan from years of exile, her life had been the object of public threats by assorted militant groups and leaders, not least among them Ayman al-Zawahiri, the principal deputy to the fugitive Al Qaeda leader Osama bin Laden. Essentially, the officials said, Bhutto's life had been under constant threat since her return to Pakistan; every time she went out in public she faced possible attack, and jihadist militants were a source of the most virulent threats.

One of the U.S. officials said that while hard evidence was at this point lacking, it is "entirely plausible" that a jihadist leader like Mehsud could have been involved in instigating or organizing the attack. Mehsud is described by the officials as one of the Taliban's most senior leaders inside Pakistan. He supposedly operates from loosely governed tribal areas along the Afghanistan-Pakistan border and is believed to be in contact with elements of the Al Qaeda central command, whose leaders, including Zawahiri and bin Laden, are believed to be hiding out in the same rugged region.