The Pakistani government is under significant public pressure to prosecute Davis. The incident has set off massive anti-American protests and calls for Davis to be executed for the murders.
"Our first fear is that the sentiment of the street in Pakistan is, 'Let's take him and hang him,'" said a current senior U.S. official.
According to the official, administration officials fear that the Pakistani government lacks sufficient control over Pakistani municipal police, who have Davis in custody.
A second U.S. official told ABC News that even Pakistani officials are concerned for Davis's safety in the Lahore prison where he now awaits his next court date. According to the official, the jail holds 4,000 inmates, many of whom are militants, and as many as three prisoners have been "murdered by guards." Davis is currently being held in a separate part of the jail for his safety, and his guards have had their guns taken away. His food is being tasted first by dogs to make sure it isn't poisoned.
U.S. officials have been in a standoff with the Pakistani government over Davis's detention since his arrest. The U.S. asserts that Davis has diplomatic immunity and is protected under the Vienna Convention, which recognizes diplomatic immunity. Pakistani officials have denied that his diplomatic passport protects him from the country's judicial system.
Last week President Obama called Davis "our diplomat" and urged the Pakistani government to release the CIA operative.
"We've got a very simple principle here that every country in the world that is party to the Vienna Convention on diplomatic relations has upheld in the past and should uphold in the future, and that is, if our diplomats are in another country, then they are not subject to that country's local prosecution," Obama said in a press conference last week.
"We expect Pakistan, that's a signatory and recognizes Mr. Davis as a diplomat, to abide by the same convention."
Since Davis was detained, the Obama administration has summoned the Pakistani ambassador to the White House to demand Davis's release, while Secretary of State Clinton and the U.S. ambassador to Pakistani and asked senior Pakistani military, intelligence and other government officials to respect Davis's diplomatic immunity. But the U.S. has refused to elaborate publicly on Davis' position in Pakistan except to say he was a "technical advisor" for the consulate in Lahore and to refer to him as a "diplomat" in public statements.
"We are playing a game of chicken," said a senior Pakistani official, who would only speak if given anonymity. "It is not yet clear who will blink first."
According to a senior U.S. official, Davis first arrived in Pakistan in December 2008, and was posted at various times in Islamabad, Lahore and Peshawar. Until last August, Davis was stationed in Pakistan as an employee of the company once known as Blackwater, now called Xe Services, and contracted to the CIA.
According to a former Blackwater executive, the CIA terminated the company's GRS contract in Pakistan, accusing the security company of failing to provide adequate services. The agency then moved to hire all the former Xe/Blackwater security personnel directly as independent contractors.