Leave your feedback Share Copy URL https://www.pbs.org/newshour/show/london-bombing-investigation Email Facebook Twitter LinkedIn Pinterest Tumblr Share on Facebook Share on Twitter Transcript A Pakistani official announced Monday that three of the four suspected suicide bombers may have visited Islamic schools in Karachi last year, as investigators continue to search for clues into the attacks in the British town of Leeds where the bombers lived. Read the Full Transcript Notice: Transcripts are machine and human generated and lightly edited for accuracy. They may contain errors. IAN WILLIAMS: More details of the movements of the London bombers are now emerging. Immigration photos leaked to a Karachi newspaper today showed two of them, Tanweer and Mohammed Sidique Khan, the Edgeway Road bomber, arriving in Karachi on Nov. 19 last year.They took a train to Lahore, leaving Pakistan on the 8 of February. Hasid Hussein was recorded entering Karachi four months earlier on July 15 on a flight from Riyadh, Saudi Arabia. It's not clear where he went on to in Pakistan.President Musharraf, in an emergency meeting with police chiefs, has ordered a crackdown on extremism. He'll follow this up with an address to the nation about the London bombings later this week, which will be keenly watched by foreign diplomats, especially after Musharraf's U.N. ambassador said Britain should look internally for the cause of the bombings and not blame Pakistan.The threat of a crackdown is one reason why the mullahs of Muridke have been keen to claim innocence.And now out of Lahore to a vast but isolated compound in the town of Muridke. Beyond the barricades, a religious school founded by an associate of Osama bin Laden. Never before have television cameras been invited by mullahs, who regard photography of living things as un-Islamic. But they agreed to give us limited access, so keen were they to deny reports of a visit here by Shehzad Tanweer.And as we toured the physics lab, I showed the school coordinator a picture of the Aldgate bomber.And you would know if he has been here? SPOKESMAN: I think I told him that I first time seen him. IAN WILLIAMS: So he's never been here, no? SPOKESMAN: Not at all, not at all. Absolutely not. IAN WILLIAMS: They were keen to show us the educational facilities on this 75-acre site, built with Saudi money. And they insisted they no longer accept foreign students.They insist they offer an all-round education here. And this is the swimming pool. They say that if British Muslims arrived, they'd be turned away, although much of what has gone on here is as murky as the water.In fact, it's one of more than a hundred madrassahs associated with Laskar-I-Taiba, Pakistan's biggest jihadi outfit which recruits young men to fight Indian rule in Kashmir, and has been associated with Pakistan's intelligence services. It's also been linked to the Taliban and al-Qaida, and under U.S. pressure was banned by Pakistan, though like so many others, it simply changed its name.Not all Pakistan's estimated 20,000 madrassahs nurture jihadis. And today, in other religious schools, less worried about being filmed, it was business as usual: Learning the Koran by heart.