An American citizen was arrested by British authorities Tuesday, accused of aiding an al-Qaida plot to stage spectacular attacks in London.
London police made the arrest as the American man was preparing to board a flight to Pakistan.
Court documents say he's Syed Hashmi, age 26, and accuse him of providing cash and military equipment for al-Qaida terrorists. U.S. officials say the military gear was intended to support al-Qaida's jihad activities overseas, especially in Afghanistan, where it could be used against U.S. soldiers.
The former head of counterterrorism for New York says Hashmi's arrest shows how persistent terrorism investigators are.
"Hashmi was a jihadi. He was interested in fighting jihad in Pakistan," says Michael Sheehan, a terrorism expert and NBC News analyst. "He had connections to serious terrorists in the U.K. He was an American citizen, a very troublesome character, and we're glad that he's been picked up."
Sheehan says many of these people are kept under surveillance for years, and the authorities move in whenever they believe they have learned enough to finally shut them down.
Law enforcement sources tell NBC News Hashmi is also suspected of playing a role in a plot to attack half a dozen targets in London, including prominent buildings in the city's financial center. That plan was broken up two years ago, when British police made arrests and discovered half a ton of fertilizer that could be used to make bombs.
Investigators say Hashmi graduated from Brooklyn College in 2003 and left the U.S. for Pakistan shortly after that.
The court documents say since January of 2004, he's been providing supplies to a contact who, in turn, took them to al-Qaida associates in South Waziristan, Pakistan, a remote area where top al-Qaida figures have long been thought to be hiding out.
Investigators say Hashmi introduced an American named Mohammad Babar to the London plotters. Babar, arrested two years ago, has admitted taking part in similar activities in Pakistan to aid al-Qaida.
Authorities stress that while they believe Hashmi was deeply involved in helping al-Qaida overseas, there's no indication that he was helping to plot any attacks here in the U.S.