An American official said the Pakistani doctor who ran the program in Abbottabad gained temporary access to the bin Laden compound but never saw bin Laden himself and failed to obtain DNA samples from bin Laden family members, the Times reported Monday.

A team of Navy SEALs killed bin Laden during a raid in May. US officials have said they were not certain bin Laden was in the compound in Abbottabad when President Barack Obama gave the go-ahead for the operation.

Dr. Shakil Afridi, who ran the vaccination program, has been arrested and held in Pakistani custody because of his suspected collaboration with the US, the Times reported.

The CIA declined to comment on the Times report when contacted by The Associated Press.

The vaccination program was first reported by the British paper The Guardian.

The bin Laden raid was kept secret from Pakistani officials, which has strained US-Pakistan relations. Bin Laden’s ability to live for years in Abbottabad, where Pakistan’s main military academy, has led to speculation in the US that some elements of the Pakistani government knew of his whereabouts.