The US is to open criminal inquiries into the deaths of two CIA detainees in Iraq and Afghanistan in 2002 and 2003.
Gul Rahman died in November 2002 at a CIA prison in Afghanistan and Manadel al-Jamadi died at Abu Ghraib prison in Iraq in 2003, according to reports.
Attorney General Eric Holder accepted the recommendation of an investigation into treatment of detainees.
But he said the probes into 101 other cases since the 9/11 attacks would lead to no other prosecutions.
Mr Holder's announcement on Thursday came more than three years after his predecessor, Michael Mukasey, appointed justice department lawyer John Durham to investigate a report that videotapes of CIA-led interrogations of prisoners were destroyed.
In August 2009, Mr Holder expanded that inquiry to covered allegations of mistreatment of detainees in CIA custody.
Rahman, described by CIA operatives as a hardened conduit between Afghan Taliban forces and al-Qaeda militants, died in November 2002 after being shackled to a cold cement wall at a CIA prison in northern Kabul, officials told news agencies.
Al-Jamadi is said to have died at Abu Ghraib prison, where he arrived wounded after a fight with US special forces in 2003.
In his initial inquiry, Mr Durham reviewed whether CIA operatives used unauthorised interrogation techniques on detainees, and examined CIA involvement in the questioning of 101 detainees following the 11 September 2001 terror attacks.
"Mr Durham and his team reviewed a tremendous volume of information pertaining to the detainees," Mr Holder said in a statement on Thursday.
"Mr Durham has advised me of the results of his investigation, and I have accepted his recommendation to conduct a full criminal investigation regarding the death in custody of two individuals. Those investigations are ongoing.
"The department has determined that an expanded criminal investigation of the remaining matters is not warranted."
The BBC's Paul Adams, in Washington, says the Obama administration has said from the start that it does not intend to prosecute anyone who acted within the scope of available legal guidance.
Under the presidency of George W Bush that guidance included a variety of techniques, including waterboarding, which are now officially regarded as torture.