A POLISH farmworker who killed his sister because of debts he owed her and her husband could have gone on to kill again, a senior policeman has admitted.

Detective Superintendent Adrian Green said police would never know whether Piotr Lawniczak also intended to murder his brother-in-law after he strangled his sister, Danuta Domagalska, before hanging himself.

Yesterday, an inquest into their deaths heard that Mr Lawniczak owed substantial amounts of money, believed to be tens of thousands of pounds, to Mrs Domagalska and her husband, Marcin.

The three Poles were living together in a workers’ cottage at New Moor Farm, in Walworth Gate, near Darlington.

Yesterday’s inquest at Chester-le-Street Magistrates’ Court heard that, after Mrs Domagalska disappeared in August last year, Mr Lawniczak weaved an elaborate web of deception to her husband, the farm staff and his family in Poland to convince everyone that his sister was alive and well.

When Sue and John Archer, the owners of the farm, became suspicious and alerted police, Mr Lawniczak disappeared.

His body was later found hanging from a tree in a wood near the farm.

A few days after that, Mrs Domagalska was found buried in a shallow grave.

Home office pathologist Dr Jennifer Bolton told the inquest that her body showed signs of strangulation.

Mr and Mrs Domagalski spoke little or no English and Det Supt Green told the hearing that Mr Lawniczak, who worked with his sister at the farm, held a very influential position in the house, acting as their translator.

Investigations revealed the couple had lent Mr Lawniczak a significant amount of money in a number of installments.

This money had been transferred to Mr Lawniczak’s wife in Poland, as well as a third party connected with a haulage company.

That money was expected to be repaid by the end of August last year. In July, Mrs Domagalska’s bank card had gone missing and subsequent inquiries revealed money had been transferred from the of her death.

Mr and Mrs Domagalski were due to attend the bank in Darlington with Mr Lawniczak to activate a new card.

Det Supt Green said: “At that time it would have been apparent that money had been transferred out of the account. It was known to Marcin and Danuta that Piotr had access to the account and it would been very quick for the bank to identify that money had been transferred to Poland.”

Mrs Domagalska attended work as usual that morning, but was not seen alive again. Mr Lawniczak told Mr and Mrs Archer that Mrs Domgalska had left to work on another farm and told his wife in Poland that he was on his way back to the country.

He told Mr Domagalski that his wife was working long shifts at the farm and, when he became suspicious, Mr Lawniczak used her mobile phone to send texts convincing her husband that she was still alive.

He kept up this pretence until August 14 when Mrs Archer alerted police.

Speaking after the inquest, Det Supt Green said an investigation was under way by authorities in Poland into what happened to the Domagalskis’ money.

He added that he did not know whether Mr Lawniczak intended to kill Mr Domagalski.

Det Supt Green said: “I honestly don’t know. I’ve asked myself that same question many times. We’ll never know. If he did, we should be very thankful he didn’t get the chance to carry it out.”

Through an interpreter, a tearful Mr Domagalski thanked police for their efforts. He said: “Thank you to every single police officer searching for my wife day and night.”

Mr Tweddle recorded that Mr Lawniczak took his own life and Mrs Domagalska was unlawfully killed.