The United States received useful information from Iranian nuclear scientist Shahram Amiri who decided to return to Iran this week, a US official said on Wednesday.
"We got useful information from him, and the Iranians got Amiri. Ask yourself who got the better deal," the official said on condition of anonymity.
The official declined to comment on any specific details about what information was provided by Amiri, who defected to the United States last year.
The CIA has a National Resettlement Operations Center for resettling defectors, but the official would not comment on its connection with Amiri.
The scientist left the United States overnight for Iran after showing up at the Iranian interests section of the Pakistani embassy in Washington, asking to go home.
Iran had accused the CIA of kidnapping Amiri, who disappeared last year during a pilgrimage to Mecca. But Secretary of State Hillary Clinton and other US officials said Amiri had been free to come and go as he pleased.