A former CIA station chief in Pakistan, who presided over the May 2011 raid that killed al Qaeda chief Osama bin Laden at his hideout in Abbottabad, is believed to have been poisoned by the powerful ISI, a media report said today.

Mark Kelton was removed from Islamabad two months after the raid on bin Laden’s compound in the garrison city of Abbottabad, citing health concerns.

“Mark Kelton retired from the CIA, and his health has recovered after he had abdominal surgery. But agency officials continue to think that it is plausible if not provable that Kelton’s sudden illness was somehow orchestrated by Pakistan’s Inter-Services Intelligence agency, known as the ISI,” The Washington Post said in an exclusive investigative report.

A spokesman of the Pakistani Embassy here, however, described the report as fictional.

According to The Post, Kelton, declined multiple requests for an interview, but in a brief exchange by phone he said that the cause of his illness “was never clarified”.

He said that he was not the first to suspect that he had been poisoned.

“The genesis for the thoughts about that didn’t originate with me,” he was quoted as saying.

The Post said such a disclosure is a disturbing postscript to the sequence of events surrounding the bin Laden operation five years ago and adds new intrigue to a counterterrorism partnership that has often been consumed by conspiracy theories.

“Even if the poisoning suspicion is groundless, the idea that the CIA and its station chief considered the ISI capable of such an act suggests that the breakdown in trust was even worse than widely assumed,” The Post said.

According to the daily, current and former US intelligence officials said that the ISI has been linked to numerous plots against journalists, diplomats and other perceived adversaries and that the spy agency’s animosity toward Kelton was intense.

Meanwhile, A CIA spokesman said there is no evidence thatPakistani authorities poisoned a US official serving in the country.