Why this businessman killed family, self in Patna?

Patna: In a sensational case that has shocked the capital of Bihar, a businessman allegedly shot his wife, daughter, son in the Kidwaipuri area. The man, identified as Sunil Saraf, then allegedly shot himself. Police have registered a case of triple murder and have initiated a probe.
According to reports, the Saraf family had returned from a vacation four days ago. On Monday night, the family, after having dinner, had gone to sleep but on Tuesday morning, it was found that Sunil had first shot his family and then shot himself dead.
Sunil, his wife Alka and daughter Ananya are dead and his son, Ishant is battling for life at a hospital. Moreover, it was said that a suicide note has also been recovered.
Meanwhile police is investigating the case and trying to figure out whether it is a case of suicide or a murder, said PK Das, city SP, Patna.