Detectives in Yorkshire are still questioning six people arrested in London believed to be part of a large Somalian organised crime gang. Police think that their associates may have been involved in the murder of WPC Sharon Beshenivsky.

WPC Sharon Beshenivsky: shot dead by armed robbers (©PA)

The armed robbers who murdered the rookie WPC during a raid on a travel agency in Yorkshire are suspected of being among the gang responsible for many crimes across London including drug dealing and more robberies.

WPC Beshenivsky, 38, and WPC Teresa Milburn, 37, were shot as they arrived at the raid on the Universal Express travel agency in Bradford . Three robbers, two with firearms and one with a knife, had tied up staff and were escaping with a quantity of money when they opened fire at the officers.

A tearful WPC Milburn following her wounding (©PA)

WPC Beshenivsky, who had three children and two step children, was pronounced dead when she arrived at hospital. WPC Milburn was shot in the shoulder and was allowed home from hospital on Sunday.

Officers are anxious to identify which gang members were in possession of a silver 4x4 vehicle that has been linked to Friday's shooting in Bradford city centre. The getaway vehicle is understood to have been traced using licence plate recognition cameras.

Witnesses have described how heavily armed police ambushed a silver 4x4 vehicle outside a store in Plumstead at 7.20am on Saturday and arrested a Somali man and white woman who were travelling in it.

Five hours later a flat was stormed in De Havilland Drive, Plumstead, by 30 officers with sub-machineguns, body armour, pistols, CS gas and helicopter back-up. Three Somali men were arrested at the rented third-floor flat.

The police raids which resulted in the arrest of the six suspects - five men and one woman - on Saturday came after a huge deployment of Scotland Yard officers. Hundreds of officers were mobilised, including specialist CO19 firearms teams, members of the armed Flying Squad unit, territorial support group officers and detectives from the specialist crime directorate. Officers from the West Yorkshire constabulary were flown to London by helicopter.

Eyewitnesses described seeing armed police storm a flat on Saturday minutes after a group of Somali men had driven up at speed, sprinted up a staircase and disappeared inside. Officers carrying sub-machine-guns and CS gas canisters surrounded the flat at about 12.15pm, shouting "get down, get down", according to witnesses. Later, they led out three Somalis, who were handcuffed with their trousers round their ankles, and made them lie face down in the road at gunpoint.

The first arrests occurred five hours earlier after two police vehicles approached the occupied silver 4x4 at speed. One eyewitness said the car had been rammed by a police vehicle to force it to stop before the armed officers surrounded it.

The woman and four of the men are in their 20s and the other man is in his early 30s. They are all from south-east London and are being held at various police stations in West Yorkshire . Further arrests are expected.

Four of the men are Somali and one Asian but immigration checks have shown nothing to suggest that any are in the country illegally.

Detectives from West Yorkshire are working with Metropolitan Police officers in London in an attempt to identify those associated with the gang.

Last night, detectives were given more time by magistrates to question the suspects held in connection with the murder of WPC Beshenivsky.