The severed head and body of a man thought to be a foreigner have been found abandoned by the River Tigris in northern Iraq, police say.
The identity of the victim, brought to Tikrit, has not been established.
Meanwhile Bulgarian authorities confirmed that another beheaded body found earlier was that of a Bulgarian lorry driver taken hostage in Iraq.
A spokeswoman for the Bulgarian Foreign Ministry said the fingerprints matched those of 30-year-old Georgi Lazov.
13 July: Bulgarian hostage beheaded
29 June: Keith Maupin, 20, US soldier is reportedly killed (not confirmed)
22 June: Kim Sun-il, 33, South Korean translator beheaded
11 May: Nick Berg, 26, US businessman beheaded
14 April: Fabrizio Quattrocchi, 36, Italian security guard shot dead
Mr Lazov and his colleague, 32-year-old Ivaylo Kepov, were seized by militants in Iraq.
They had been delivering cars from Bulgaria to the Iraqi city of Mosul.
Militants led by suspected al-Qaeda militant Abu Musab al-Zarqawi earlier released video of one of the men being decapitated.
A correspondent for the French news agency AFP who saw the new set of remains after they were taken to Tikrit said they had begun to decompose.
An Iraqi police official, Col Ismail al-Jubburi, said the body did not appear to be that of an Iraqi.
Reports differ as to where the new body was found with AFP giving the location as al-Zuwiya and Reuters and others saying it had been found in the city of Baiji.
Col Jubburi said the remains were found in a plastic bag.
The video of the beheading was received by Arab broadcaster al-Jazeera and the militants also threatened to kill a second Bulgarian captive.
Bulgaria, which has contributed almost 500 troops to the US-led coalition in Iraq, ruled out withdrawing its forces in response to any demands by hostage-takers.