A former FBI agent who went missing in Iran was working for the CIA there, not conducting private business as officials have previously claimed

A former FBI agent who went missing in Iran was working for the CIA there, not conducting private business as officials have previously claimed, The Associated Press and the Washington Post reported on Thursday.

Both the State Department and Bob Levinson's family have long denied he was working for the U.S. government when he disappeared on a trip to Iran in 2007.

But Thursday's reports from the Washington Post and the AP claim that Levinson had been on a CIA mission to dig up information.

A source who's involved in the matter told CNN that there's proof that Levinson worked for the CIA undercover and under contract while also working as a private investigator.

The AP says it decided to move forward with publishing the sensitive story after holding off several times.

"The AP first confirmed Levinson's CIA ties in 2010 and continued reporting to uncover more details. It agreed three times to delay publishing the story because the U.S. government said it was pursuing promising leads to get him home," the news agency said in its report. "The AP is reporting the story now because, nearly seven years after his disappearance, those efforts have repeatedly come up empty. The government has not received any sign of life in nearly three years. Top U.S. officials, meanwhile, say his captors almost certainly already know about his CIA association."

CNN's source, who declined to be identified because of the sensitive nature of the investigation, said that after six and half years in captivity and interrogations, it's more than likely that Levinson's captors know he was working undercover.