Delivering the verdict, Additional Sessions Judge Sarvamangala acquitted one person for lack of evidence.
The prosecution case was that four persons hired the autorickshaw on April 10, 2011 from Perundurai and directed him to take them to a place. After travelling some distance, the four strangulated him to death, dumped his body near the village and escaped with the vehicle.
Police launched a search and nabbed three of them within days of the murder.
A search is on for one more person, who is still at large.