“Amit doubted that his wife was having an affair with one of her colleagues. He had heard her talking to him on phone a number of times on Saturday,” inspector G Nagaraj of the Koramangala police station said.

“Following a heated argument and a scuffle between the couple, Amit suffocated Rinku to death using a pillow,” he added.

The police declined to name Rinku’s colleague as investigations were on.

Rinku, a chartered accountant from Mumbai, was working with a private bank. Amit and Rinku had got married about a year ago.

The murder that took place between 6 and 7 pm on Saturday came to light on Sunday when Rinku’s friend came to their house. They were to go to a movie together, the police said. When there was no response to repeated calls, the house owner, who stays on the ground floor, was alerted and the police were informed.

The police entered the first-floor house in the upscale Koramangala area with the help of a duplicate key the house owner had and found the two bodies and the suicide note.

The bodies have been sent for postmortem.

“Their parents have been informed in Delhi and Mumbai. They are reaching here on Monday,” Nagaraj said.

The police are talking to the house owner, neighbours and colleagues and friends of the couple to find out whether there was any other motive for the crime other than what Budhiraja said in his suicide note.