The Bandipur police station registered a case of murder and unnatural death. (Representational)

A 36-year-old Mysuru businessman allegedly shot dead his parents, wife and son before killing himself near Bandipur in Karnataka's Chamarajanagar district, the police said on Friday.

"Omprakash and his 4-member family appear to have entered into a suicide pact, unable to bear the harassment of debtors and the burden of mounting losses from his businesses, including a call centre, real estate and mining at Mysuru and Bengaluru," Chamarajanagar Superintendent of Police HD Anand Kumar said.

The police said that though Mr Omprakash and his family lived in Mysuru, they drove to a rented farmhouse on Thursday near Bandipur for an overnight stay. He then sent away his driver and an attendant, asking them to come back the next morning.

After dinner, the family went out in an open field where Mr Omprakash allegedly shot his parents, wife and son, before shooting himself with a pistol in the wee hours, Mr Kumar said, citing the preliminary report on the incident and visuals taken of the crime scene for investigation.

Mr Omprakash's father was identified as Nagaraja, 65, mother Hema, 60, his wife Nikitha, 36, who was 8 months pregnant, and 4-year-old son Aryan Krishna.

"The incident came to light when Omprakash's driver and attendant returned to the farmhouse earlier in the day and found them missing inside. On searching around, the two found their bullet-ridden bodies in a grass field. They informed the police and an FIR was filed based on their deposition," the police said.

The 0.32 inch bore pistol which Mr Omprakash used in the crime is a licensed firearm of his gunman that was in his car.

The Bandipur police station registered a case of murder and unnatural death under various sections of the Indian Penal Code and investigation is underway to ascertain the reasons for the alleged suicide pact.

"The five bodies were handed over to Omprakash's sister after autopsy at a state-run hospital and were taken on road to Mysuru for the last rites," added Mr Kumar.