24/08/2012 11:33 BST | Updated 24/08/2012 12:17 BST

Damian Rzeszowski Guilty Of Manslaughter Of Six People, Including Wife And Children

A man who carried out a frenzied knife attack on six people, including his wife and two young children, has been found guilty of manslaughter.

Damian Rzeszowski armed himself with kitchen knives and stabbed his father-in-law Marek Gartska, 56, wife Izabela Rzeszowska, 30, daughter Kinga, five, and two-year-old son Kacper, at their Jersey home on 14 August last year.

The 31-year-old Polish builder also turned on his wife's friend, Marta De La Haye, 34, and her five-year-old daughter Julia, who were at the house for a barbecue.

Rzeszowski was convicted of six counts of manslaughter on Friday following a trial at the Royal Court in St Helier, Jersey.

Kinga and Kacper Rzeszowski

The court heard that Rzeszowski's marriage had been under strain after his wife confessed to a two-month affair with another man and threatened to commit suicide.

Rzeszowski admitted the killings but his defence argued that he was suffering moderate to severe depression, causing an onset of psychotic symptoms which diminished his responsibility.

Wearing a white T-shirt and jeans, Rzeszowski showed no emotion in the dock as the presiding judge, Sir Michael Birt, read out the verdicts that two jurats - similar to magistrates in the UK - had reached.

Throughout the trial, the defendant had constantly stared down at the floor, not looking up at any time.

Mrs De La Haye and her daughter

No members of the victims' families were in court, but the public gallery was full of curious onlookers.

Judge Birt, who is the Bailiff of Jersey, said Rzeszowski would be sentenced for manslaughter on 29 October.

He also thanked counsel and the interpreter who assisted Rzeszowski throughout the trial for their hard work.

The prosecution had argued that Rzeszowski was guilty of murder after rejecting manslaughter pleas he entered in April.

Izabela Rzeszowska admitted to her husband she had been having an affair

Solicitor General Howard Sharp claimed the defendant had not been suffering an abnormality of the mind which substantially impaired his responsibility when he attacked his family.

During the trial, the court heard Rzeszowski lashed out as his marriage crumbled.

In June last year, his wife told him she had been involved in a two-month affair with another man and threatened to kill herself.

He had previously caught her flirting with other men online and she had confessed she no longer loved him.

In turn, he retaliated with a one-night stand of his own which he told his wife about.

But after Rzeszowski took an overdose of pills on 19 July 2011, the couple agreed they would try to save their marriage.

The stabbings happened on the day the family returned to Jersey after a holiday in Poland which was intended to get their relationship back on track.