The video clip of the murder was found on the man's mobile phone.
A seven-year-old boy was murdered in his sleep allegedly by his father because of pressure from his stepmother, the police said on Tuesday in Madhya Pradesh's Indore.
Prateek, a Class 3 student, usually slept with his grandparents. On Sunday, his 26-year-old father, Shashipal Munde, allegedly told him to sleep in his room, which had a cooler.
The boy, excited about the cooler, told his grandparents he was going to his father's room. That was the last they saw him alive.
According to the police, when his son fell asleep, Shashipal turned up the TV volume and strangled him. He allegedly tried to videocall his wife, but she didn't take it.
After killing his young son, Shashipal, allegedly shared the video as proof with Payal, his third wife, on WhatsApp, but she could not see it as she had blocked his mobile number.
He later ran away.
Both Shashipal and Payal, 23, were arrested On Tuesday.
"I had also sent this video and a message to Payal that now my son will never trouble her as I have killed him," Shashipal told reporters.
Payal had recently given birth to a baby boy and had allegedly told Shashipal she wouldn't return from her parent's home unless he got rid of Prateek, his son from a previous marriage.
"Shashipal Munde's third wife was very upset with the boy from the beginning. They often quarrelled on the issue," police officer Jaiveer Singh Bhadoria said.
Payal had told her husband that she would return only if he sent away his son or killed him, Mr Bhadoria said.
The video clip of the murder was found on Shashipal Munde's mobile phone.
Payal said she had nothing to do with the crime. "I never told my husband to kill his seven-year-old son," she said to the media.