10 of 40 'infiltrators' still at large
Agents in the US have identified around 40 infiltrators who had a hand in the attacks on the World Trade Centre and the Pentagon.
10 of those are believed to be still at large, while the others either died in the suicide attacks or are unaccounted for.
It has also emerged that the hijackers wrote suicide notes to their parents before the attacks. The notes were found at addresses across the east coast.
With most of the evidence pointing towards Saudi dissident Osama bin Laden, more than a dozen of the men who hijacked the four planes have now been identified.
Around 4,000 FBI agents worked to track down the men, with the investigation stretching from the Canadian border in the north to Florida in the south.
In total, 27 of the attackers are believed to have received flight training.
The FBI has searched addresses in the states of Massachusetts, New Jersey and Florida and have issued photographs of two of the men they believe were responsible for the attacks.
Computer equipment was seized from two houses in the Vero Beach area of Florida and one man, believed to be an acquaintance of the two suspects, was detained.
Both houses had been occupied by another two suspects, brothers who are believed to have been aboard one of the planes which smashed into the World Trade Centre.
Elsewhere, three men were taken into custody for questioning after an inter-city train from Boston was stopped and searched in Providence, Rhode Island.
