Presumed Innocent & Punishment for adultery
In Islam, with 4 witnesses the adulterer(s) are stoned to death; fornicators are treated differently. In the presence of circumstantial evidence - around which the fate of accused in the movie rested - the guilty goes to jail for whole lot of years, as per religious scholars of Pakistan (at least).
One can ponder over the wisdom behind this divine injunction in many ways. One logic the movie provided is the rage, disintegration and destruction adultery brings to family which makes its punishment - in the presence of such strict condition - much more severe and applicable. Surely as Deterrence to say the least. Deterrence is something Islam so much professes in theory and practice from national defense to self-matters.