Raymond Davis was arrested for killing two youngsters in Lahore last week.
Davis was produced in court under a tight security cover after his six-day remand period ended Thursday, Dawn TV reported. According to the Pakistan government, he is in the country on a diplomatic passport.
"The police contended that they were yet to complete investigation with Davis and requested the court to extend the remand. The court extended the remand for another eight days till Feb 11," the report said.
The court, however, granted bail to Davis in another case of carrying arms illegally and asked his lawyers to submit the bail bonds of Rs.100,000.
The bail bonds were submitted before the court but Davis could not be set free because of the extension of his police remand in the alleged twin murder, the television report said.
Davis, a member of US consulate's technical and administrative staff, shot two youngsters in Lahore Jan 27 and claimed acting in self defence alleging that the two were trying to rob him at an ATM machine.
All efforts by the US authorities to secure his release under diplomatic immunity have so far been turned down by the government. The Lahore High Court has also barred him from leaving Pakistan.