By THOMAS WAGNERAssociated Press Writer

The mangled carriage where seven people died in the terror attack near Edgware Road Tube station in London is being lifted by crane off the track and on to a flatbed lorry, Tuesday after the carriage had been winched out of the tunnel at the station where the explosion happened on July 7. The sealed carriage will be transported to a secure police compound for further forensic examination. (AP Photo/ Stefan Rousseau, PA) LONDON — A Pakistani intelligence official said Wednesday that authorities had arrested an ‘‘important’’ suspect in the London bombings, while police in London removed a shattered carriage from a subway station, signaling a shift in the investigation’s underground forensic work.

‘‘We have an important man in our custody,’’ a senior Pakistani intelligence official told The Associated Press. ‘‘I am not in a position to disclose his name right now, but the maximum that I can tell you is that he has some direct links with the London attacks.’’

Speaking in the eastern city of Lahore, the official declined to say when the man was arrested or elaborate on his alleged links with the London bombings. The official spoke on condition of anonymity because he is not authorized to speak to the media and because of the secretive nature of his job. Pakistani police earlier reported arresting seven people with links to the bombings.

British detectives continued to hunt for the masterminds of the attacks that killed 56 people, but The Times newspaper reported Wednesday that authorities remain uncertain whether an organizer slipped out of Britain just before the July 7 blasts on three Underground trains and a doubledecker bus.

The carriage was removed late Tuesday from the Edgware Road station, one of two attack sites on the Circle Line around central London.

The 20-ton car, shrouded in blue tarpaulins, was removed to a secure police facility for farther investigation.

London Underground said it hopes to resume full service on the line by Aug. 2.

Key questions remain unanswered in the investigation, Metropolitan Police Commissioner Sir Ian Blair said Tuesday, including: ‘‘Who is the chemist? Who are the people who trained them? Who facilitated their trip to Pakistan?’’

‘‘Whoever is doing that is still out there,’’ Blair told a meeting of Christians, Muslims and Jews. The Times quoted unidentified police sources as saying they believe a man visited London and the hometowns of the four suspected suicide bombers, but left hours before the attacks. However, it quoted unidentified security sources as saying they had ruled out one suspected organizer as a case of mistaken identity.

The Egyptian government said Tuesday that Magdy el-Nashar, a biochemist who taught at Leeds University and is wanted for questioning by Britain, had no links to the attacks or to al-Qaida. Leeds is the hometown of two men identified by police as suicide bombers. Three of the London suspects — Hasib Hussain, 18, Mohammed Sidique Khan, 30, and Shahzad Tanweer, 22, all Britons of Pakistani descent — traveled to Karachi in southern Pakistan last year, and Pakistani security officials believe Tanweer spent a few days at a religious school in Lahore, where many militant groups have operations.