British security officials hunting for Margaret Hassan are trying to contact the intermediary who acted as the conduit with Abu Musab al-Zarqawi's group during the kidnapping of Kenneth Bigley.
They want to ascertain whether it is Zarqawi's, or another group, that is holding the Iraqi-UK aid worker Margaret Hassan, 59, and whether they can negotiate her release.
Unusually, Zarqawi's Tawhid and Jihad (One God and Holy War) has not declared it is holding Hassan and the video of her is marked by the absence of either its banners or gunmen lording it over its new captive.
Margaret Hassan's husband Tahseen Ali Hassan yesterday begged the kidnappers to free her. Speaking on Al-Arabiya television he said: 'I plead with you, in the name of Islam and Arabism - while we are in the most sacred Islamic month - that my wife and beloved return to me.' The secretary-general of Care International, Denis Caillaux also appealed to her kidnappers, pointing out that she is a naturalised Iraqi citizen 'and always holds the people of Iraq in her heart'.
Amid marked differences between the two kidnap pings, British officials conceded yesterday that they have 'no idea' who snatched Mrs Hassan, the director for Care International in Iraq, who has given 30 years of her life to relieve the suffering of ordinary Iraqis.
Although the official would not say whether the contact between British government staff and Mr Bigley's kidnappers was initiated in the first place at the instigation of Zarqawi's group, what is now clear is that they regard the unidentified inter mediary as credibly representing the demands of Tawhid and Jihad.
Although the Jordanian terrorist's group is one suspect, others include groups that call themselves the Ansar al Sunna (Brotherhood of the Sayings of the Prophet) and the Islamic Army.
'It has many of the hallmarks of Zarqawi or people loosely linked to his group,' said one source. The three groups, which do not have clearly defined memberships or structures, have been responsible for the bulk of the hostage-taking in recent months in Iraq. They have also been blamed for almost all the executions.
The moves come as Prime Minister Tony Blair and Foreign Secretary Jack Straw have been asked to take a back seat in appeals for the release of Mrs Hassan, with Care International taking the lead.
Mrs Hassan, who was born in Dublin, was seized as she drove to work last Tuesday. Since then two videos of her have been passed to the al-Jazeera television station from 'the usual sources'.
The second video, which emerged on Friday, showed Mrs Hassan weeping, begging for her life and asking the British people to persuade Blair not to deploy British troops further north if she was to escape the same fate as Mr Bigley, who was beheaded at the end of his ordeal.
The video surfaced the day after Britain announced that it would move 850 troops from southern Iraq to a region near Baghdad to cover for US forces which are likely to be sent to attack Falluja.
The American military is widely believed to be preparing for a large-scale assault on Falluja, in line with a pledge by the US-backed interim Iraqi government to retake all rebel-held cities to enable all Iraqis to vote in nationwide elections scheduled for January.
The violence continued in Iraq yesterday. Suicide bombers killed 20 members of Iraq's fledgling security forces near a US marine base west of Baghdad and at a checkpoint north of the capital in a spate of attacks across the country.
Hospital officials said 16 Iraqi police were killed and up to 40 people were wounded when a suicide bomber struck an Iraqi police post near the marine base.
Another suicide bomber blew up his vehicle near a checkpoint manned by Iraqi National Guards in the village of Ishaqi, close to the town of Samarra, north of Baghdad, killing four guards. A policeman was killed by a roadside bomb in Samarra.
Elsewhere across the Sunni Arab heartland of central Iraq two Turkish truckers were killed and two others wounded in an attack on a convoy near Mosul.