An 80-year-old Italian man who swallowed a viagra pill after his wife promised to have sex with him at Christmas stabbed her to death when she changed her mind and refused.

The incident happened in the town Fanano di Gradara in the Italian region of Marche on the night between 25th and 26th December.

The suspect, named as Vito Cangini, is accused of killing his wife Natalia Kyrychok, 61, because she refused to have sex with him despite earlier promising she would before he took the pill.

The refusal prompted a furious row, during which he said he suspected her of not being interested because she was more interested in her boss, and he stabbed her to death after she turned down his advances, according to local media.

Afterwards, he reportedly left his wife’s bloodied body on the floor and went to bed.

The following morning, he ate breakfast, walked his dog, and came home like nothing had happened, according to reports.

He took his dog for another walk in the afternoon and reportedly told a neighbour what he had done and asked him to call the police. However, the neighbour did not want to get involved and told him to do it himself.

When Cangini returned home, a woman called his wife and he allegedly told her about the incident and asked her to call the police, but she probably did not believe the elderly man and did not report it either.

According to local media, he then phoned the restaurant where his wife had worked as a chef for two years and told the owner that he would never see her again, adding: “I know there was something going on between you two.”

The restaurant owner called the police and officers found the victim’s body when they visited the suspect’s home.

The victim reportedly suffered at least four stab wounds including one to the heart. The autopsy results have yet to be released.

Cangini was taken into custody and the suspected murder weapon was found at the crime scene.

The investigation is ongoing.