An ITBP constable allegedly killed his wife, daughter and son at his house on Tuesday on the suspicion that she was having extra-marital affairs, at Pathroli village of Jhunjhunu district, police said.
Sarita (30), son Nitin (11) and daughter Priti (9) were stoned to death by Indo-Tibetan Border Police personnel Anil Kumar Yadav, who was posted in Delhi, deputy superintendent of police Pacheri, Suresh Sanwaria said.
He suspected his wife of having illicit relations, he said.
Yadav later surrendered before the police at Patchier police station confessing his involvement in the crime, Sanwaria said, adding that he was immediately arrested.
A case was registered under section 302 (murder) of the IPC, he said. The bodies were sent for postmortem, he said.
Hundreds of locals gathered at the crime site on learning about the incident after which police had to push them away to conduct inquiry.