Arrests reported in London bombings

Investigators in the London bombings said Tuesday they are focusing on four men, at least one of whom "very likely" died in one of the blasts. They also said that they had made an arrest in the investigation.

Identity documents of the four men were found very near the explosions, Peter Clarke, head of Scotland Yard's anti-terrorist branch, told reporters. Closed-circuit TV video showed that all four had arrived together at King�s Cross station 20 minutes before the first blast, he added.

Clarke said that one of the four men under suspicion "very likely" died in one bombing, and that one person had been arrested in raids earlier Tuesday in Leeds, a city 185 miles north of London.

He added that at least three of the four men were from West Yorkshire, the county where Leeds is located.

Police and Army troops were led to six properties in Leeds after identifying a suspected bomber who died in the bus bombing, sources told the Press Association, a British news service. Scotland Yard refused to confirm the claims.

Earlier reports had quoted a witness on the bus who said he saw an �agitated� olive-skinned man rummaging in a backpack moments before the explosion.

The Leeds homes were searched and found to be unoccupied.

Several neighbors told NBC News that the area had been home to several young Pakistani men who had not been seen since before the bombings Thursday. The father of one man has been interviewed by police, NBC reported.

At one address, army experts carried out a controlled explosion to gain entry to the property and then helped police search it for explosives, Inspector Miles Himsworth of West Yorkshire Police told reporters.

Hours earlier, police searched five residences in the Beeston area of Leeds.

Himsworth said some material had been seized from the houses but would not elaborate.

In Luton, a city just north of London, police closed off the railway station and adjoining car park after coming across the vehicle suspected of being tied to the bombings.

Nearby streets were cordoned off, and police later blew up the car as a precaution. Located next to a regional airport, the Luton station is on the rail line that goes to King's Cross station, one of the three bombed last Thursday.