The bodies of two British hostages handed over in Iraq have been identified, the BBC has learned.
The families have been told, and are being given time to inform their relatives, the BBC's security correspondent Frank Gardner said.
The names of the two hostages are expected to be released later today.
IT consultant Peter Moore, from Lincoln, and four security guards were captured by armed militants at the Ministry of Finance in Baghdad in 2007.
The Foreign Office said it had "grave concerns" over the safety of the three other men still thought to be held by the kidnappers, our correspondent said.
"This is incredibly tough for the families because there really was so much optimism," he added. "This was a blow out of nowhere."
Frank Gardner, BBC security correspondent
"It does appear the two hostages died some time ago.
It's not yet known how they died, and we've got to keep an open mind on this until the coroner decides how they died.
They could have been executed, the could have died trying to escape, they could have died of starvation.
The kidnappers always maintained that one of the prisoners in their care committed suicide."
It's possible the handover of the bodies could be seen as a trade-off for the release of a militant, Laith al-Khazali, on 6 June.
His freedom had been a stipulation for the hostages being freed, Frank Gardner said.
The remains of the two dead men were handed over to Iraqi authorities on Friday night, and were then passed on to the British Embassy in Iraq.
Little is known about the identities of the men because of a media blackout during a large period of their captivity.
The blackout originally came on the instruction of the hostage-takers who said they did not want publicity.
Mr Moore had been working for American management consultancy Bearingpoint when he was kidnapped, while the other men were contractors employed to guard him.
The names of the four security guards are understood to be Jason, Alan, Jason and Alec.
Little else is known about them, other than that the guard Alan is from Dumbarton in Scotland and at least one other is from South Wales.
Click to view image: 'British Hostage'
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