depends on the nature of the crime... I can't help resist thinking about harsh public execution being warranted for certain types of serious crimes especially those that affect the society at large and if the perpetrator was a repeat offender - e.g. I have no sympathy for rapists, and child molesters.
It should be the way Al-sunnah prescribes. A woman who is suspected of having relationship with other man should be stoned to death in front of the public or someone who was raped a woman, or a woman who is cheating her husband as per Islamic scholars or moulvis prescribe.