Washington has identified the Saudi-born Islamic militant, Osama Bin Laden, as a key suspect behind the attacks.

BBC: Q&A: Military options

Berezovsky was immediately fingered by the police as a key suspect, but the murder remains unsolved two years later.

FORBES: Godfather of the Kremlin?

And yet when it came to the key suspect, Seamus Daly - who the RUC believed had been the "hands-on" organiser of the bombing - there was nothing to show he had even been questioned by the Gardai about the mobile phone analysis that pointed to his role.

BBC: Cross border co-operation was a myth

At the weekend, the LAPD's chief of police said the department would re-examine the case that led to Dorner losing his job, a key grievance in the suspect's online essay.

BBC: Charred body found after US manhunt for Christopher Dorner

"Sir Alex Ferguson makes key decisions very quickly and I suspect he will have been very much involved in what has happened, " said Hughes.

BBC: Hughes expects big transfer spree

It has been the standard approach for decades but now a High Court judge has interpreted the legislation as saying that once four days have passed, including the period on bail, detectives must have new evidence (key phrase) before they can force Suspect Sam back to the station.

BBC: Police bail in the dock

India's top investigation agency has removed a key member of its prosecution team from his post for alleged links with a suspect in a corruption scandal.

BBC: India's CBI removes telecoms scandal prosecutor