Special Agent Joel Cox, confirmed by the US State Department as an FBI agent, was arrested on Sunday (May 4) at the airport after trying to board a flight with the knife and fifteen 9mm rounds in his luggage.
Cox had yet to leave the court, a witness said. Bail conditions included a payment of one million rupees ($10,000).
COMMENT: All foreign law enforcement officers traveling to Pakistan should be sensitized as to the importance of NEVER transporting any form of weapon aboard a commercial aircraft, knowing how sensitive the Pakistanis are in terms of engaging in some "pay-back" for the Navy SEAL raid that executed Osama bin Laden.
The case has revived memories of Raymond Davis, a US Central Intelligence Agency contractor who was arrested in January 2011 after shooting and killing two Pakistanis who he believed were intent in robbing him in Lahore.
Many Pakistanis were angry that Davis was released after compensation was paid to the families of the dead and resulting in his being pardoned, a practice allowed under Pakistani law.
Cox appeared in court on Tuesday (May 6) on what police said were charges of carrying unauthorized ammunition on a civilian flight and was remanded into custody.
His equipment, including his laptop, has been sent to a forensic laboratory for testing, which may result in sensitive information being compromised.
"This individual detained is an employee of the FBI, who was on a temporary duty assignment to provide routine assistance to the legal attaché at the U.S. mission," US Department of State spokeswoman Jen Psaki said in her daily briefing in Washington on Wednesday (May 7).
The Davis case demonstrated the deep suspicion on both sides that pervades the ultra-sensitive alliance between the United States and Pakistan.