Most countries when presented with evidence that someone who lives there did something criminal will arrest and turn the criminal over to the country the crime was committed in. Sometimes they will put some stipulation in (Europe commonly won't turn a murderer over until the country promises not to seek the death penalty for example), but in general criminals are turned over all the time. In general a country doesn't want criminals living there even if the crime was done elsewhere and so they won't protect their own who commit a crime.

I don't know Pakistan's polices, but I would expect they would turn the criminal over to the US.