Updated 2:30 p.m. ET
A failed plot to set off bombs in the New York subway system last year was part of larger al Qaeda conspiracy that planned a similar attack in England, U.S. prosecutors said Wednesday.
In a terrorism indictment unsealed Wednesday, prosecutors added several al Qaeda figures to the case, including Adnan Shukrijumah, whose name is on the FBI's list of most-wanted terrorists.
Shukrijumah, an al Qaeda leader in charge of plotting attacks worldwide, was directly involved in recruiting and plotting the New York attack, prosecutors said. Attorney General Eric Holder has called that plot one of the most dangerous since Sept. 11, 2001.
According to prosecutors, the September, 2009 plot to attack the New York Subway system involving Najibullah Zazi - a legal resident living in Colorado - "was also directly related to a scheme by al Qaeda plotters in Pakistan to use Western operatives to attack a target in the United Kingdom."
Two of the men indicted Wednesday, Abid Naseer and Tariq Ur Rehman, were linked to a previously undisclosed companion plot in England.
"These charges underscore the global nature of the terrorist threat we face," David Kris, the Justice Department's top national security prosecutor said.
After 9/11, Shukrijumah, 34, was seen as one of al Qaeda's best chances to attack inside the United States or Europe, captured terrorist Abu Zubaydah told U.S. authorities. Shukrijumah studied at a community college in Florida, but when the FBI showed up to arrest him as a material witness to a terrorism case in 2003, he already had left the country.
In 2004, then-Attorney General John Ashcroft called Shukrijumah a "clear and present danger" to the United States. The U.S. government is offering a $5 million reward for information leading to his capture.
Intelligence officials began unraveling the subway plot last year, when U.S. intelligence intercepted an e-mail from an account that al Qaeda had used in a recent terrorist plot, officials said. The e-mail discussed bomb-making techniques and was sent to an address in Denver, setting off alarms within the CIA and FBI from Islamabad to the U.S.
Three U.S. citizens were arrested in September 2009 before, prosecutors said, they could carry out a trio of suicide bombings in Manhattan. Zazi pleaded guilty to his role in the New York subway plot on February 22; co-conspirator Zarein Ahmedzay pleaded guilty on April 23.
A third man, Adis Medunjanin, awaits trial. Prosecutors added new terrorism charges against him Wednesday.
A fourth suspect, a midlevel al Qaeda operative, identified by the Justice Department only ask "Ahmad," traded the e-mails with Zazi, who was frantically trying to perfect his bomb making recipe, officials said. The U.S. wants to bring the Pakistani man to the U.S. for trial on charges that are not yet public.
"Ahmad" was also communicating with Manchester-based, United Kingdom resident "Naseer," officials said. Naseer "used coded language to refer to different types of explosives" in e-mails with Ahmad and referred to planning a "wedding" - which investigators believe was code for a terror attack.
Pakistani officials also have arrested a fifth person, known as Afridi, who worked with Ahmed, officials said.
Prosecutors have said the men, motivated by their anger at the U.S. war in Afghanistan, traveled to Peshawar, Pakistan, in the summer of 2008 to fight against U.S. forces.
The three men arrested in September men stayed at the house of Zazi's uncle before splitting up, officials told the AP. Zazi remained in Peshawar while Ahmedzay and Medunjanin headed into Afghanistan to a Taliban stronghold where they hoped to join the fight against the Americans, officials said.
But Ahmedzay and Medunjanin never made it. They were stopped at a roadblock and briefly detained by Pakistani police who were suspicious of the Ahmedzay's Western looks and their U.S. passports. The two men talked their way out of the bind, however, and Pakistani police never contacted the U.S. about it, officials said.
Undeterred, the men regrouped in Peshawar and were recruited to meet an al Qaeda facilitator at local mosque in Peshawar. While al Qaeda was eager to recruit Americans, the group was also deeply suspicious of the trio and wanted to make sure they were not U.S. spies.
Once they passed that initial test, Ahmed drove them to North Waziristan and delivered them to a rudimentary terrorist camp. The three received weapons training, but al Qaeda had bigger plans for the men than the Afghanistan front line.
Salah al-Somali, then the head of external operations, and Rashid Rauf, a British militant linked to a 2006 jetliner bomb plot, explained to the three men that they were more useful as suicide bombers in the United States.
It was at that camp that counterterrorism officials believe Ahmedzay, and perhaps the other two men, met Shukrijumah, one of al Qaeda's up-and-coming figures. In 2004 then-Attorney General John Ashcroft called Shukrijumah a "clear and present danger" to the United States. Captured terrorist Abu Zubaydah told U.S. authorities that Shukrijumah was among the most likely candidates to attack the U.S. or Europe.
The trio completed about two weeks of training and left the camp with the promise of returning. But only Zazi made the trip back to the Waziristan to take a course on explosives.
Zazi flew to New York in early 2009 and moved to Denver, armed with bomb-making notes from Pakistan. Unlike the Sept. 11, 2001, attacks they chose the target, not Osama bin Laden.
Prosecutors said Wednesday that " after Zazi was already in custody, Medunjanin attempted to crash his car into another car on the Whitestone Expressway in Queens, N.Y. as a last attempt to carry out a suicide attack on American soil. Just before crashing his car, Medunjanin called 911 to identify himself and announce his intentions."
He remains in federal custody.