Neighbours previously bequeathed a man's home, claimed he was bullied before making a new will a week before he died, the High Court has heard.
William and Maureen Watton also alleged Robert Warke was told by his nephew, that they would put his dog down if he passed away.
Details emerged in a ruling about the costs of their aborted bid to have his last will and testament set aside.
Mr Warke died in June 2014, leaving his home at Glencarna Court in Coleraine, its contents and his dog, to his nephew Hugh Crawford.
The will, drawn up a week earlier, also included a £10,000 cash bequest to Mr and Mrs Watton.
But in a previous will, dated March 2013, Mr Warke left his home and pets to the Wattons.
They issued legal action, claiming their neighbour did not have sufficient capacity or soundness of mind to make the changes to his arrangements.
An alternative argument was also advanced, that the last will and testament was the product of Mr Crawford's undue influence.
Proceedings were discontinued, however, after the case was listed for hearing in June.
Delivering judgment yesterday on the dispute about costs, Mr Justice Horner set out the plaintiffs' allegations that Mr Crawford had bullied the deceased.
The new will was executed while they were away on holidays, the court heard.
It was their case that they had cared for Mr Warke as friends and neighbours, looking after his dog when he was unable to do so.
A further allegation was made, that Mr Crawford told his uncle the Wattons would put the animal down if he died.
No evidence has been made available to support the Wattons' claims.
During correspondence between the legal teams, Mr Crawford's solicitors confirmed they were satisfied his uncle had testamentary capacity to make his last will.
In his ruling, the judge said claims made in the proceedings were not supported by any contemporaneous documents.
Although he described the defendant's response to requests to see the earlier will as "tardy and unsatisfactory", the majority of blame for the "unnecessary" commencement of legal action was attributed to the plaintiffs and their solicitors.