A man killed his wife and pet dog before jumping to death from an apartment building in the southern Indian state of Karnataka on Tuesday.

Atul Upadhyay, 58, lived with his wife, their nephew and a pet dog in the apartment. The incident took place after the nephew left for college Tuesday morning. The couple allegedly got into an argument and in a fit of rage, Upadhyay killed his wife by hitting her with a dumbbell on the head. He then killed his dog by throwing it off the terrace, before jumping to death.

Upon hearing a loud sound, the security rushed to the main gate to find the bodies of Upadhyay and the dog lying on the ground. Police personnel were called to the scene.

“We found Atul’s wife dead in a pool of blood in the hall of their flat and a bloodstained dumbbell next to her,” a police officer told local daily the Times Of India.

A note found by the police from the apartment read, “Cancer is a dangerous disease. This is better than cancer. This is not selfishness." It was, however, unclear if it was Upadhyay or his wife suffering from cancer.

"We've no clue why Atul took the extreme step, besides coming across an envelope that has noted, mostly about cancer," a police officer said, adding, "He did not mention who - he or wife - was suffering from cancer. He didn't mention why he killed his wife and dog."

Some reports, however, suggested his wife was suffering from an advanced-stage cancer which did not have any cure and that the couple was reportedly upset about it. There was no official confirmation about it.

india crime Representational image of police officials investigating a crime scene in Bangalore, Karnataka, in southern India, Sept. 5, 2017. Photo: MANJUNATH KIRAN/AFP/Getty Images

The police officer said they did not know until Tuesday evening that their nephew was living with them.

"The boy told us his uncle and aunt were talking to each other in the hall when he left for college,” the officer said.

A housekeeping staff at the apartment said the couple treated the pet like their child.

"I have been working here for six years, and the couple doted the dog,” he said.

Police said they have collected evidence from the home and the bodies of the man and his wife were sent for autopsy. The dog’s body was kept at a veterinary hospital.