Why can't Afzal be hanged?

The man who was the master mind behind the attack on Indian Parliament ..in other words he put the entire nation to shame. The judiciary did thier bit and convicted him. Where is the delay? Afzal has now challeged the govt by by saying only Advani can hang him. What is govt fearing? Loosing minority votes or making an impression on janta that NDA is a strong govt. The option two would go a long way to send message across to oppsition and all others speculating.