Whats your opinion in the case of Border Patrol agents Ignacio Ramos and Jose Compean?

In 2006 both of these men were sentenced to 12 years (solitary confinement, due to threats from those they have previously arrested) for shooting admitted and now convicted Mexican drug smuggler Osvaldo Adlrete Davila and trying to cover up the incident. Do you believe that they should be pardoned under these cirstance, Or should they serve out their sentence due to police corruption & lies?