London bombers: Key facts

Police have revealed important developments in the hunt for those responsible for the London bomb attacks.

BOMBERS

Three of the four bombers were British nationals of Pakistani descent from West Yorkshire

They were: Mohammad Sidique Khan, 30, of Dewsbury; Hasib Mir Hussain, 18, of Holbeck, Leeds: and Shehzad Tanweer, 22, of Beeston, Leeds

The fourth bomber was Jamaican-born Germaine Lindsay who lived in Buckinghamshire

Hussain was the Tavistock Square bomber and Tanweer was responsible for the Aldgate attack. Khan was the Edgware Road bomber, and Lindsay was responsible for the King's Cross attack

CCTV stills and a picture of Hasib Hussain were released by police

Officials in Pakistan have supplied documentation showing that Khan and Tanweer visited Pakistan during 2004

Police are now hunting those who supported, financed, encouraged and armed them

A suspected al-Qaeda member entered the UK via a Channel port two weeks before the bombings, but was not put under surveillance. He flew out a couple of hours before the bombs went off

Explosives found in a house in Leeds are said to be similar to those used in al-Qaeda attacks and made from ingredients available in high-street chemists

Met Police Commissioner Sir Ian Blair said he expected the investigation to uncover a "clear al-Qaeda link"

EVENTS IN LONDON

The four men were captured on CCTV at King's Cross station, wearing rucksacks, shortly before 0830 BST on the morning of the attacks

The men had travelled to King's Cross on a Thameslink train from Luton. CCTV footage of them in Luton has also been released in an attempt to find out more about what they were doing

At King's Cross, they split up, three of them detonating their bombs on separate trains simultaneously at 0850 BST

Hussain's bomb went off 57 minutes later, at Tavistock Square.

The blasts killed a total of 56 people, including the bombers

The blast at Kings Cross killed 27 people, 14 died on the bombed bus at Tavistock Square, the attack at Edgware Rd killed seven and the Aldgate blast killed eight.

Police sources have told the BBC they have not recovered any timing devices from the bomb scenes, possibly indicating that detonation was by hand

Hussain had been reported missing by his family, and personal belongings of some of the group were found at the bomb scenes

Counter-terrorism officials believe the group of four would have had an outside "controlling hand" who could still be at large

More than 3,500 calls have been made by the public to an anti-terrorist hotline and police have taken more than 800 witness statements.

Police are also analysing more than 6,000 CCTV tapes

1 The four men arrive at King's Cross Thameslink station from Luton. They go to the tube station and fan out on different lines
2 Shehzad Tanweer takes the Circle line eastbound. Bomb explodes between Liverpool St and Aldgate
3 Lindsey Germaine takes the Piccadilly line south. The train blows up before the first stop at Russell Square
4 Mohammad Sidique Khan takes the Circle line westbound. Bomb explodes at Edgware Rd
5 Hasib Hussain may have tried the Northern line but he ends up on the No. 30 bus. Bomb explodes at Tavistock Square

LEEDS INQUIRY

One man has been arrested in West Yorkshire and is being questioned in London. He is believed to be related to one of the suspected bombers

Police have searched the homes of three of the four suspects in West Yorkshire and have executed search warrants at 10 addresses in the region

A controlled explosion was carried out in the Burley area

Police evacuated a number of homes in areas being searched

Home-made explosives were found

LUTON AND AYLESBURY INQUIRIES

Forensic experts are still examining a property in Aylesbury, Bucks. No arrests have been made and no explosives found

Two cars in Luton, one of which had explosives in it, are connected to the inquiry. Police spent 14 hours dealing with explosive devices found in one car at Luton Central railway station

The other car was towed to nearby Leighton Buzzard

It is thought the cars were hired by the suspects in West Yorkshire before being driven to Luton

Three of the men travelled down to Luton from West Yorkshire

There they met a fourth man who had driven to Luton

All four caught a Thameslink train to London King's Cross

Police found two suspect cars in Luton station car park

DEVELOPMENTS OUTSIDE BRITAIN

A Leeds-based chemistry student, Magdi al-Nashar, was cleared of involvement by the Egyptian government after being arrested in Cairo on the request of British officials

A number of people have been arrested and are being questioned in Pakistan as part of the inquiry