A DISGRUNTLED Jehovah’s Witness is being sued, by the family he poisoned, for $100,000 because his malicious, spiteful crime has left them feeling anguished and afraid.

The Advertiser can reveal Karen and Ben Anthonysz have filed civil action against Brett Darren Mardon, who was last month convicted of lacing their food and drink with weed killer.

In court documents, Mrs Anthonysz, 43, says her youngest child still asks his food be checked, while her bakery suffered because she could not ensure the purity of its ingredients.

She fears Mardon’s choice of toxin, glysophate, may cause the family hormonal disruption and “DNA damage”, or leave them susceptible to Parkinson’s disease and cancer.

Mrs Athonysz says she and her husband — a church elder who excommunicated Mardon for infidelity — “struggled to comprehend” the bizarre offending to which they fell victim.

“I still can’t understand why someone would want to hurt us and our children, and cause us so much anguish and concern,” she says.

“My husband has felt very angry that Mardon targeted me and the children when his issue was with my husband, not us.

“We’ve struggled to comprehend why Mardon would target us in this way ... he carried out these acts maliciously, out of spite, intending to cause us mental stress.”

Mardon, 47, was found guilty at trial of three counts of attempting to create a risk of harm and three counts of serious criminal trespass in a place of residence.

He also pleaded guilty to two counts of theft.

As first revealed by the Sunday Mail, Mardon repeatedly broke into the Anthonysz’s home and used a syringe to inject glysophate into their milk and juice.

Prosecutors alleged claimed Mardon’s use of the weed killer was motivated by revenge, as he blamed Mr Anthonysz, 49, for his excommunication and the end of his marriage.

Mardon, however, said his goal was to “emotionally disturb” Mr Anthonysz so he would leave the church, ending his period of disfellowship, and that he intended no harm.

Judge Rauf Soulio rejected that submission as “unconvincing and somewhat irrational”.

In Adelaide Magistrates Court documents, viewed by The Advertiser, Mrs Anthonysz says her eldest son was the first to suggest their food was being poisoned, rather than spoiling.

“That was the first we had even contemplated that someone would do such a thing,” she said.

“Our youngest child still asks us to check his food and drink sometimes, as it became such an ingrained habit for all of us to do it.”

She says she has developed post-traumatic stress disorder as a result of Mardon’s crimes.

“I’ve experienced a lot of stress, worry and concern ... I feel his behaviour was a gross invasion of our privacy and a major threat to our personal security,” she says.

Mr and Mrs Anthonysz ask the court to award them $100,000 compensation to cover medical expenses, the cost of the poisoned food, damages and court costs.

Mardon, who is on bail awaiting sentencing submissions next month, has yet to file a defence to the claim.