(US) ABC News reported it:
ABC News, citing unidentified officials, reported on Thursday that the attacks were connected to an al-Qaida plot planned two years ago in Lahore.
Names on a computer that authorities seized last year from Muhammad Naeem Noor Khan, an alleged Pakistani computer expert for al-Qaida, matched a suspected cell of young Britons of Pakistani origin, most of whom lived near Luton, where the alleged suicide bombers met up on their way to London shortly before last week's blasts, according to the report.
Authorities have now discovered ties between Mohammed Sidique Khan one of the July 7 bombers and members of that cell who were arrested last year, ABC said.
Pakistani intelligence officials reached by The Associated Press would not immediately confirm that report, though they said that information taken from Noor Khan's computer indicated plans for an attack in London, as was reported at the time of his arrest last year.
http://abcnews.go.com/International/wireStory?id=941402&page=2There has also been talk that Sidique Khan was linked to the investigation in which
half a ton of ammonium nitrate was found, which was earlier in 2004:
Some British and European counterterrorism officials have raised concerns that at least two of the bombers might have been known to the police as part of two sprawling terrorism investigations in 2004: the investigation of an alleged attempt in the spring to build an enormous fertilizer bomb to strike somewhere in London, and the arrest of a small cell of men in August who were accused of plotting to attack financial buildings in Manhattan, Newark and Washington, D.C.
Questions have been raised, for example, why domestic intelligence agents did not determine that Mohammad Sidique Khan, one of the four bombers, was a threat to national security in 2004. Early last year, Britain investigated him in connection with the alleged plot to build the fertilizer bomb and use it in London, according to several European-based counterterrorism officials. British officials have refused to confirm whether Mr. Khan, 22, of Leeds, was a suspect in that investigation, or answer questions about why they did not monitor his activities.
http://www.nytimes.com/2005/07/19/international/europe/19intel.html?pagewanted=print