The accused opened fire at the duo and also shot and injured his daughter.
A former Army man allegedly shot dead his brother and nephew and injured his daughter after they intervened while he was quarrelling with his wife at their house in Madhya Pradesh's Sagar district, police said on Saturday.
The police have arrested the accused Ramadhar Tiwari (50) in connection with the shooting that took place in Lalepur village, around 15 km from the district headquarters, on Friday, inspector R P Dubey of Sanodha police station said.
Ramadhar was quarrelling with his wife Sandhya when his elder brother Rammilan (62) and nephew Ajju (36) intervened to pacify him, he said.
The accused opened fire at the duo and also shot and injured his daughter Varsha (24) outside their house, the official said.
Ramadhar then escaped from the scene in his car and was apprehended hours later, he said.
The two men succumbed to their injuries at a hospital, while the woman is undergoing treatment at Bundelkhand Medical College, the official said.
Talking to reporters, Superintendent of Police Abhishekh Tiwari said the accused was a former Army man, and he committed the murders with a licenced firearm.
According to the police, the accused has four daughters and a son. Two of his children were in school at the time of the shooting.