Along with the former officials, they provided few details about the targets of the raids in Iraq and Afghanistan, although they said that many of the Iraq raids were directed against members of Al Qaeda in Mesopotamia. To corroborate the claims of the company’s involvement, a former Blackwater security guard provided photographs to The Times that he said he took during the raids. They showed detainees and armed men whom he and a former company official identified as Blackwater employees. The former intelligence officials said that Blackwater’s work with the C.I.A. in Iraq and Afghanistan had grown out of its early contracts with the spy agency to provide security for the C.I.A. stations in both countries.

Image In 2007, an Iraqi traffic police officer inspected a destroyed car in a square in Baghdad, where Blackwater guards killed 17 people in an incident that stirred outrage among Iraqis. Credit... Khalid Mohammed/Associated Press

In the spring of 2002, Erik Prince, the founder of Blackwater, offered to help the spy agency guard its makeshift Afghan station in the Ariana Hotel in Kabul. Not long after Mr. Prince signed the security contract with Alvin B. Krongard, then the C.I.A.’s third-ranking official, dozens of Blackwater personnel  many of them former members of units of the Navy Seals or Army Delta Force  were sent to provide perimeter security for the C.I.A. station.

But the company’s role soon changed as Blackwater operatives began accompanying C.I.A. case officers on missions, according to former employees and intelligence officials.

A similar progression happened in Iraq, where Blackwater was first hired for “static security” of the Baghdad station. In addition, Blackwater was charged with providing personal security for C.I.A. officers wherever they traveled in the two countries. That meant that Blackwater personnel accompanied the officers even on offensive operations sometimes begun in conjunction with Delta Force or Navy Seals teams.

A former senior C.I.A. official said that Blackwater’s role expanded in 2005 as the Iraqi insurgency intensified. Fearful of the death or capture of one of its officers, the agency banned officers from leaving the Green Zone in Baghdad without security escorts, the official said.

That gave Blackwater greater influence over C.I.A. clandestine operations, since company personnel helped decide the safest way to conduct the missions.

The former American intelligence officials said that Blackwater guards were supposed to only provide perimeter security during raids, leaving it up to C.I.A. officers and Special Operations military personnel to capture or kill suspected insurgents or other targets.