Intelligence officials say no one knows for certain who is behind the upsurge in terrorist attacks in Iraq. But there are a number of theories, including the possible involvement of ousted Iraqi leader Saddam Hussein.

Just a glance at the headlines of major U.S. newspapers makes clear the uncertainty about who is the mastermind behind the latest bomb, rocket and other attacks in Iraq.

The New York Times said some U.S. officials see Saddam Hussein's hand in the bloody strikes, while the Los Angeles Times quotes intelligence sources as saying they see a foreign hand, like al-Qaida's, in the blasts.

Still other reports in recent days have quoted officials as saying a former top aide to Saddam, Izzat Ibrahim al-Douri, is to blame - and that he may be coordinating attacks with foreigners.

But one defense intelligence official told VOA, "We don't really know for sure." This official, speaking on condition of anonymity, confirms a number of sources have come forward to report this-or-that about who is responsible for the attacks.

But the official said none of these sources have a great deal of credibility and the reports are conflicting.

Still, the notion that Saddam Hussein could be involved has captured considerable attention - particularly since the ousted Iraqi leader has not been captured.

In a speech late Thursday, Defense Secretary Donald Rumsfeld acknowledged that having Saddam at large is not conducive to restoring security in Iraq. "The fact that he's alive is unhelpful. Let there be no doubt...So we do need to catch him and I think we will. When, I don't know," Mr. Rumsfeld said.

Mr. Rumsfeld's comments came as some U.S. television organizations broadcast highly-sanitized versions of what has been dubbed a "torture tape" - a captured Iraqi videotape showing gruesome scenes of prisoners being tortured and executed under the regime of the ousted president.

Mr. Rumsfeld said he has seen such a tape and it confirms why it was imperative to topple Saddam's regime. "When you have people filming, in front of crowds cheering and clapping, you have people cutting off people's tongues, and cutting off people's heads, and chopping off their fingers and chopping off their hands, throwing them off three-story buildings, you learn something about a group of people and how they live their lives and how they treated their people. And we are so fortunate they are gone and that those 23 million people are liberated," he said.

U.S.-led coalition forces have tracked down and killed Saddam's sons, Uday and Qusay. But so far the former Iraqi leader has managed to avoid the effort that has been focused mainly on the area around his hometown, Tikrit, long suspected as his most likely hideout.

Administration officials have up until now portrayed Saddam as a man on the run. But the latest New York Times report quoted officials as saying he now could be a leader in the armed opposition to the U.S.-led coalition in Iraq.