Additional District Judge I, Satya Prakash Sinha found the four accused - Rahul Kisku, Jhota alias Gurucharan Singh, Suresh Tudu and Binod Hansda-- guilty and convicted them under relevant sections of the Indian Penal Code, police said.
The court will pronounce the quantum of punishment on Friday.
Two other accused, however, turned out to be juvenile and the concerned board was hearing their case, police said.
According to the FIR lodged under the Patamda Police station, the accused persons had protested and smashed the glasspanes of the victims' car on finding the woman, a management intern, and her paramour in a comprising position inside the vehicle behind on July 15, 2011.
Following the incident, the woman had escaped from the spot and ran towards a nearby village but the accused chased and caught hold of her a little distance away and raped her in turn.