Unidentified gunmen shot dead an Uttar Pradesh-based businessman, his wife and their 25-year-old son outside their house in Sitapur on Tuesday night, ANI reported. No arrests have been made in the case so far.

Police officials said it was a case of suspected robbery as the accused fled with cash. “The people seemed to be resisting a robbery attempt,” Additional Director General of Police, Abhay Kumar Prasad told NDTV. “A similar robbery attempt was made on another trader a few days ago.”

The attackers shot at 60-year-old Sunil Jaiswal and his son, Ritwik, when the two had arrived outside their residence. They killed Jaiswal’s wife, Kamini, when she ran outside the house after hearing the gunshots. While the parents died on the spot, the son succumbed to his injuries in a hospital.

The assailants also shot at one of Jaiswal’s neighbours, who had tried to intervene, but the police said he survived and managed to inform them about the incident. The local traders’ association have called for a shutdown if the assailants are not arrested within 24 hours, according to NDTV.

Uttar Pradesh has witnessed similar incidents in recent past. A 36-year-old businessman was shot dead in Allahabad last week. In May, a man was shot dead and four women alleged they were gangraped on the highway near Utttar Pradesh’s Jewar.