The murder was discovered by the victim's brother. [In file: Secured by forensic specialists of the German police blood is spread on the floor at the crime scene after a deadly knife attack on May 10, 2016, in Grafing, Bavaria]Johannes Simon/Getty Images [Representational Image]

A 58-year-old man murders his wife in Bengaluru, kills their pet dog and commits suicide by jumping off from the apartment building on Tuesday (April 2) morning.

Atul Upadhyay, a businessman, who used to run a travel agency NockNock Analytics in Ulsoor allegedly killed his wife Mamata Upadhyay by hitting her with a dumbbell on the head. He then killed their pet Labrador dog by throwing it off from the terrace and then he too jumped off from the building.

The couple used to live in the fourth floor of Annex Sycon Polaris Apartment in the upscale Sadashiva Nagar. Atul's nephew (brother's son) Rishabh, studying law in a private college in the city stayed with the couple as they did not have any children. Rishabh left for college around 9 am after which the incident took place.

In the death note found by the police, it is alleged that Mamata was diagnosed with advanced stage of cancer and the couple did not want to suffer from any depression, hence they took this extreme step. "Cancer is a dangerous disease. This is better than cancer. This is not selfishness", read the note.

According to Rishabh, the couple were very upset about Mamata's cancer. The couple did not have any relatives in the city other than Rishabh. Atul's relatives in Mumbai and Mamata's sister in the United States have been informed about the incident.

"We've no clue why Atul took the extreme step, besides coming across an envelope that has noted, mostly about cancer," S Girish, DCP (central), said. Police said they didn't know until evening that Atul's nephew, studying law in a private college, was also living with them. "The boy told us his uncle and aunt were talking to each other in the hall when he left for college around 9 am," a police officer said, reports Bangalore Mirror.

Their mortal remains are kept at MS Ramaiah memorial hospital for autopsy and the pet dog's body is kept at a veterinary hospital. The post-mortem will be conducted after the relatives of the deceased arrives.