A British inquiry on Wednesday ruled that UK troops mistreated nine Iraqi detainees in violation of the Geneva Convention following a fierce battle in 2004.
The report said that some soldiers had used "tactical questioning" techniques like food and sleep deprivation with their prisoners and took "tasteless trophies", like photos with detainees.
But the report said that allegations of murder and torture were the product of "deliberate lies, reckless speculation and ingrained hostility" from the detainees.
The Al-Sweady Inquiry was set up in the aftermath of a notorious firefight near the town of Majar al-Kabir, southwest Iraq, that came to be known as the "Battle of Danny Boy" after the name of a nearby checkpoint.
Troops had been accused of unlawfully killing 20 or more Iraqis at Camp Abu Naji near Majar-al-Kabir in May 2004 after they were taken prisoner following the battle, which was triggered when Iraqi insurgents mounted an ambush.
But former judge Thayne Forbes, who led the inquiry named after one of the dead men, 19-year-old Hamid Al-Sweady, found they were killed in battle.
Forbes began in March 2013 hearing the nearly 300 witnesses who testified. The probe cost nearly £25 million (32 million euros, $39 million).
Forbes on Wednesday said the treatment of nine detainees who had taken part in the battle "amounted to actual or possible ill-treatment".
But lawyers for the claimants had earlier admitted there was "insufficient material" to assert that Iraqi civilians were unlawfully killed in custody.
However, the lawyers had stressed there were "numerous allegations of violent and other ill-treatment of Iraqi Civilians in British custody which the Inquiry will have to consider".