A Perth father had been suffering from a mysterious illness, which he claimed cleared up only when he went away on holiday.

Robert Knapinski, 64, was suspicious that his wife Bozena, 63, had been deliberately making him sick. In a bid to prove what she was up to, Robert swapped his meal for his son’s as his wife looked on.

He had also set up hidden cameras around the home, which revealed his wife of over 40 years was pouring dangerously toxic levels of selenium into his drinking water.

Ms Knapinski is accused of poisoning her husband with selenium (Nine News)

After capturing the footage, he reported his wife to the police, and she was arrested in April 2023. Instead of drinking the water, Knapinski managed to hide 13 bottles away, which were then given to the police for testing.

She is now standing trial at the Supreme Court of West Australia, where she is accused of poisoning her husband and has pleaded not guilty to six counts of intent to harm endangering the life of another person.

Clinical toxicologist Dr Kerry Hoggett explained just how high the selenium levels were in the bottles, at 140 to 1100 times higher than Australian drinking water guidelines.

Ms Knapinski insists she did nothing wrong and just wanted to make him ‘more vibrant’ and was ‘doing it to make him feel better’, the Daily Mail reports.

Her lawyer has called her former husband a hypochondriac. She insists she was trying to help Robert with his health and to improve their marriage.

Bozena’s lawyer, Michael Tudori, says his client often worked two jobs and did most of the housework and cleaning. They claim that Robert complained daily ‘about some medical pain or suffering’.

However, Robert insists his now ex-wife was actually upset about an affair he had, which he says took place during a seven month ‘separation’ in 2021, and that she said she ‘would forgive but not forget’. During the time of separation, Ms Knapinski had moved into a bedroom upstairs in the home they shared together.

Robert accused his ex of spiking his water (Getty Stock Image)

Robert had said he had been feeling unwell for years, but became suspicious in 2022, after he suddenly felt better when he went on holiday without his wife, during a four month trip to Poland.

When he returned from his travels, he decided to put his wife to the test, and chose to swap some of his food with their son’s plate, while she was looking.

He explained to the court why he did this: “[I was] just testing her reaction – I would think, if she poisoned something, she would react.”

Mr Knapinski confirmed he has been out of work for 40 years since suffering a back injury in 1988, but could not explain the nature of the injury or how it happened.

Mr Knapinski told the court he had received a meagre disability pension since the incident.

He denied the defence team’s claims that his ex-wife did the lion’s share of working and raising their son.

State prosecutor Brett Tooker said of their marriage: “As the years progressed, it became very unhealthy.”

Mr Tudori said Robert Knapinski ‘went to numerous specialists, dozens of specialists, dozens of other practitioners, he complained about lots of issues including a rash on his neck and abdominal issues going back a decade’.

They insisted that Ms Knapinski hadn’t meant to harm him, and insisted her ex-husband was a ‘hypochondriac’.

The trial continues.