Additional District and Sessions Court (11) Judge A Badharudheen found Viswarajan guilty of committing the crimes and awarded the maximum punishment considering the case rarest of the rare.
The 32-year-old woman, an employee in a shop in the town, was waylaid by the accused in a lonely place while she was returning home from work.
Though she was rushed to hospital by the local people, she succumbed to injuries.
The case had created a sensation after the issue was taken up by several women outfits in the state.