Cameron called the shooting of Pat Finucane "an appalling crime" and acknowledged collusion between the British Army and loyalist paramilitaries, The Guardian reported. But he said no further investigation is needed beyond the report by a prominent British lawyer that found no evidence British government ministers were involved in the killing.
Speaking in the House of Commons, Cameron said the Finucane family has suffered "grievous wrongs."
"I am deeply sorry," he said.
Finucane, a solicitor involved in a number of human rights cases, was gunned down as he ate dinner with his wife and three children in their home in Belfast. Ken Barrett, an Ulster Defense Association member who was also a British Army informer, pleaded guilty in 2004.
The report by Sir Desmond de Silva said that the Royal Ulster Constabulary Special Branch and the British military intelligence services decided not to warn Finucane he was at risk because they did not want to compromise one of their agents. There was also a political motive, de Silva suggested.
"Steps were often not taken to secure the protection of those who were considered to be a thorn in the side of the security forces during this period of the Troubles," he said.
Geraldine Finucane, who was wounded by her husband's killers, called the de Silva report a "sham." She and her children appeared at a news conference outside the Parliament building.
"The British government has engineered a suppression of the truth behind the murder of my husband," she said. "At every turn it is clear that this report has done exactly what was required -- to give the benefit of the doubt to the state, its cabinet and ministers, to the army, to the intelligence services and to itself. At every turn, dead witnesses have been blamed and defunct agencies found wanting. Serving personnel and active state departments appear to have been excused."