The death of two of the British hostages in Iraq, if confirmed, shows what a lethally dangerous country it remains.
Only 10 days ago it seemed likely a deal was being struck under which five Britons would be exchanged for a senior Shia militia leader and his followers.
The breakthrough appeared to be the freeing of Laith al-Khazali, a leader of Asaib al-Haq, an Iranian-backed militia group. Iraqi and American officials confirmed that an agreement was being worked out whereby Asaib al-Haq would join the political mainstream and hand over heavy weapons in return for its leaders being transferred by the Americans to the Iraqi government, which would free them.
The most important figure who would have been released under the deal was Qais al-Khazali, the brother of Laith and leader of Asaib al-Haq, who was detained by British forces in Basra in March 2007.
In retaliation, Peter Moore, a British computer expert, and four British guards were seized in a raid by men dressed in police uniforms on the Finance Ministry in Baghdad in May 2007.
Groups such as al-Qa'ida in Iraq have frequently killed their hostages in order to spread terror. The kidnapping of the five Britons was clearly aimed at securing the release of the Shia militants and an important member of Lebanese Hizbollah who had been assisting them.
The difficulty in arranging any exchange was compounded by the belief of the US military that the Khazali brothers had masterminded an attack on a base in Kerbala early in 2007 in which five US soldiers were killed.
At the time of the brothers' arrest, the US said they had documents containing detailed military information about the US camp. Several of the American soldiers who died had been captured and later killed, suggesting that this may have been an attempt to acquire US hostages that went wrong.
Both the attack on the base at Kerbala and the raid on the Finance Ministry in Baghdad were expertly organised, implying the involvement of Iranian-trained Special Groups. The Iranian participation, though difficult to pin down, appeared to make it less likely that the hostages would be killed.
The fact that two of the hostages are dead was a secret well-kept in Baghdad, though there had been an earlier report that one of them, named Jason, had committed suicide.
An Iraqi source said the release of Qais al-Khazali could be expected soon because the US was handing over all its prisoners to the Iraqi government under the terms of the Status of Forces Agreement (SODA), which was signed by the US and Iraq last year.
The source added that the US was expected to release by the end of the month the so-called "Arbil Five", five Iranian officials captured in a controversial US helicopter raid on the Kurdish capital, Arbil, in early 2007.
The freeing of the Iranian officials, long demanded by Tehran, was described by the source as one of a series of measures taken by the Obama administration to reduce tension with Iran.
However, the release of the Iranian officials may have been blown off course by the crisis in Tehran.
It has never been clear where Mr Moore and the four other British captives were being held; there was some suspicion that they had been moved to Iran.
Qais al-Khazali was originally a spokesman for the movement of the Shia anti-American cleric Muqtada al-Sadr, before breaking away to lead Asaib al-Haq, but the group's connection to the rest of the Sadrist movement was always cloudy. The kidnappers sought to keep their demands in the public eye by releasing four videos, in one of which the suicide of "Jason" is mentioned.
A further sign of how dangerous Iraq remains, despite some recent improvements in security, came yesterday when a truck bomb exploded outside a Shia mosque in the town of Taza, south of Kirkuk in northern Iraq. The blast killed at least 55 people and wounded 200 as they left the mosque at the end of prayers.