The incident occurred at around 2.30 am when Dada Rao (40) attacked his wife and son with an axe at their house in Gundegaon village under Bhainsa mandal of the district, resulting in the death of his 12-year-old son Maruti, they said.
His wife Kavitha, who suffered severe head injuries in the incident, continues to remain unconscious, they said, based on preliminary information.
"Dada Rao was allegedly in an inebriated condition when the incident occurred. Presuming that his wife and son had died in the incident, he later consumed pesticide and committed suicide," Bhainsa Rural Circle Inspector K Vinod said.
A probe is on into the incident, he added.