A cloth trader in Patna allegedly shot himself with his licensed pistol after shooting his wife and daughter in Kidwaipuri area, police said on Tuesday.
The man's four-year-old son, whom he also shot at, is said to be in a critical condition in hospital, they said.
"Prima facie, it seems to be a case of suicide. A suicide note has also been found from the spot. It indicates that the man first shot at his wife, daughter and son, and then committed suicide by shooting himself," Inspector General Sunil Kumar said in Patna.
An investigation in the incident is underway, police added.