WASHINGTON – The Justice Department announced Thursday it has ended its investigation into CIA interrogations of terrorist detainees without bringing criminal charges.

Thursday’s decision in the probes of the deaths of two terrorist suspects marks the end of a wide-ranging criminal investigation by federal prosecutor John Durham into interrogation practices during the presidency of George W. Bush.

In the past three years, Durham has looked into the treatment of 101 detainees in U.S. custody since the Sept. 11, 2001, terrorist attacks.

Durham’s probe into another episode involving the CIA began in January 2008 when the Justice Department chose him to conduct a criminal investigation into the agency’s destruction of videotapes it had made of its interrogations of terrorist suspects.

In August 2009, Attorney General Eric Holder expanded Durham’s mandate to include a preliminary review of the CIA’s interrogation of specific detainees overseas. In June 2011, Holder approved Durham’s request to move into a full criminal investigation of the two deaths.

In regard to the probe of the two detainees’ deaths, Holder said that “based on the fully developed factual record concerning the two deaths, the department has declined prosecution because the admissible evidence would not be sufficient to obtain and sustain a conviction beyond a reasonable doubt.”

In a message to employees Thursday, CIA Director David Petraeus said that “as intelligence officers, our inclination, of course, is to look ahead to the challenges of the future rather than backwards at those of the past. Nonetheless, it was very important that we supported fully the Justice Department in its efforts.”

Thursday’s announcement came in the deaths of Gul Rahman and Manadel al-Jamadi.

Rahman died in the early hours of Nov. 20, 2002, after being shackled to a cold concrete wall in a secret CIA prison in northern Kabul, Afghanistan, known as the Salt Pit. He was suspected of links to the terrorist group al-Qaida. Rahman is the only detainee known to have died in a CIA-run prison.