A US intelligence agent arrested after shooting dead two men was the acting head of the CIA in Pakistan and had been gathering intelligence for drone attacks, according to intelligence sources.
Raymond Davis, a 36-year-old former special forces soldier, had taken command after the CIA station chief’s cover was blown, according to reports.
American officials insist he is entitled to diplomatic immunity and that he be released immediately.
Davis has been held for almost a month in a Lahore prison while a court decides his status.
The case has provoked a surge in anti-American hostility and spawned a wave of conspiracy theories.
Many Pakistanis have questioned whether Davis was really the victim of an attempted robbery – as he told police – and exactly why he was driving around Lahore with a Glock handgun in a rented car.
This week it emerged that he was employed by the CIA and that he was engaged in an undercover operation.