The district and sessions court judge S S Sisodia held Sanjay Gupta guilty of scalding Sharad Chandra Hardia (60) and his wife Vijaya (55) with acid, which resulted in their death.
The court also imposed a fine of Rs 5,000 on Gupta.
According to the prosecution, the incident occurred on December 12, 2008 when Gupta went to the house of the couple in Sadar area and asked for their son Bhupendra, whose wedding was fixed with a 25-year-old woman with whom Gupta was reportedly having an affair.
Gupta had been threatening Bhupendra to stay away from the woman. He was arrested from a telephone booth from where he was threatening Bhupendra.