Confusion surrounds Karachi bombing

Police inspect the wreckage of car destroyed in a bomb attack outside the U.S. Consulate in Karachi, Pakistan.

KARACHI, Pakistan -- Investigators who first blamed a suicide bomber for a deadly blast outside the U.S. consulate are examining whether it was caused by a remote-controlled bomb hidden in a driver's education car taking three women to get licenses.

Friday's explosion killed 12 people and injured 50 as it blew a gaping hole in the heavily guarded consulate's perimeter wall, shattered windows a block away and sent debris flying a half-mile.

The widespread devastation made it difficult to piece together events leading up to the bombing and even the precise death toll was confused in the aftermath of the explosion.

Officials, citing confusion in sorting out body parts, were unsure whether 10 or 11 had died in the blast. On Sunday they said there were now 12 dead after one of the casualties died from injuries sustained in the blast.

CNN NewsPass VIDEO CNN's Chris Burns has more on the investigation of the Karachi bombing Play video Burns describes the bombing aftermath Play video   AUDIO Pakistani government spokesman Major General Rashid Qureshi on the investigations. 2.44MB / 3min. 52secs. WAV sound   RESOURCES On the Scene: Azhar Abbas: Possible al Qaeda link?  Gallery: Karachi car bomb

Officials first said they thought a suicide bomber was responsible. But attention focused Saturday on the driver's school car that was carrying an instructor and three female students.

Police said the bomb may have been stashed in the vehicle by someone who knew it would pass by the consulate and who detonated the explosives by radio from nearby.

Al Qaeda regrouping

Analysts say Friday's attack suggests the al Qaeda terrorist network is attempting a comeback after being battered by U.S. attacks in Afghanistan.

The car-bombing was the third deadly attack on a Western target in Pakistan since March.

Coalition intelligence sources now believe al Qaeda's leadership is regrouping somewhere in eastern Afghanistan or western Pakistan and is out to show it can still launch terrorist operations, big and small.

"Al Qaeda has a sophisticated strategy to engage the enemy -- not just with big attacks, but to create a climate of fear," said Magnus Ranstorp, a terrorism analyst at Scotland's University of St. Andrews. "They prey on that, and they use that to rally support."

The arrest last month of an American citizen that U.S. officials say was part of a plot to explode a radioactive "dirty bomb" is another sign that the terrorist network blamed for the September 11 terrorist attacks on New York and Washington is trying to rebuild itself.

Large numbers of al Qaeda operatives trained in neighboring Afghanistan while it was ruled by the Taliban. A U.S.-led bombing campaign led to the Taliban's overthrow last year. At least one top al Qaeda figure, military chief Mohammed Atef, was killed in U.S. raids. But most -- including al Qaeda founder and leader Osama bin Laden -- remain at large.

U.S., British and Afghan forces have pursued al Qaeda fighters along the Afghan-Pakistani border, and another top al Qaeda operative, Abu Zubaydah, was arrested in Pakistan with U.S. assistance. Two days before the Karachi bombing, Pakistani investigators said they had arrested five more suspects linked to Padilla and the "dirty bomb" plot.

Coalition intelligence sources and terrorism experts believe al Qaeda is still capable of pulling off complicated, simultaneous attacks. In the short term, however, they expect the group to launch small-scale operations to demonstrate they are not defeated.

A previously unknown militant group called Al-Qanoon -- "The Law" -- claimed responsibility for Friday's car bomb in Karachi and warned the attack was just "the beginning." In Washington, the State Department said it suspected al Qaeda was behind the attack.

Deadly potential

A senior State Department official said the consulate bombing resembled a bombing last month on a bus in Karachi that killed 14 people, including 11 French nationals. The official also said the size of the explosion had the earmark of al Qaeda.

"Pakistani groups haven't demonstrated that level of sophistication," this official noted.

A grenade attack in March on a church in Islamabad killed 5, including two Americans.

In addition to al Qaeda, suspicion in the Karachi bombing has fallen on Muslim militants that President Pervez Musharraf has been cracking down on in recent months.

Not only has Musharraf joined the U.S.-led war against al Qaeda, he has stepped up efforts to stop militants crossing into the Indian-controlled section of Kashmir, the mostly Muslim Himalayan territory both India and Pakistan claim -- where an ongoing battle against Indian rule has threatened to draw south Asia's nuclear-armed rivals into war.

"There are a lot of people, however much in the minority ... who are not happy with Pakistan's war on terrorism, and these extremist elements could also be responsible," said Maj. Gen. Rashid Qureshi, a Pakistani government spokesman.

Rohan Gunaratna, the author of a book on al Qaeda, said the group still possesses great potential for violence and may be getting help from Middle Eastern militant groups like Hezbollah.

"It was the training that was provided by Hezbollah in southern Lebanon to al Qaeda trainers that gave al Qaeda the copability to conduct terrorist operations -- especially the art of multiple suicide attacks, and in a coordinated fashion," Gunaratna said.

FBI agents were taking the lead in the investigation of Friday's bombing at the U.S. Consulate in Karachi, a U.S. diplomatic source said Saturday. A source at the U.S. consulate said the FBI was sending additional investigators and security personnel to Karachi, while keeping a close eye on other consulates as well as the U.S. Embassy in Islamabad.

-- CNN correspondents Mike Boettcher and Chris Burns contributed to this report.