About $1 million provided by the CIA to a secret Afghan government fund ended up in the hands of al Qaeda in 2010 when it was used to pay a ransom for an Afghan diplomat, the New York Times reported on Saturday.

Al Qaeda leader Osama bin Laden had at first been concerned about the payment, fearing the CIA knew about the money and had tainted it with poison, radiation or a tracking device, the Times said, and suggested it be converted to another currency.

The newspaper said letters about the ransom payment were found in the 2011 raid by U.S. Navy SEALS who killed bin Laden at his compound in Abbottabad, Pakistan. The communications were submitted as evidence in the trial of Abid Naseer, who was convicted this month in New York of supporting terrorism and plotting to bomb a shopping center in Manchester, England.

The Times said Abdul Khaliq Farahi was the Afghan consul general in Peshawar, Pakistan, when he was kidnapped in 2008 and handed over to al Qaeda. He was released two years later after Afghanistan paid al Qaeda $5 million, a fifth of which was CIA money that came from an Afghan government fund that received monthly cash deliveries from the agency, the Times said.