Debra Plum is suing the state of NSW for nervous shock, claiming the arresting officers failed to properly search her son Jason Plum before putting him in a caged wagon on August 14, 2011.

Mr Plum was carrying a small pistol which he used to deliberately inflict a single gunshot wound to his head as he arrived at Wagga Wagga police station.

The 37-year-old local rugby league identity had been arrested following a domestic dispute with his on-off girlfriend Natalie McLoon. He managed to conceal the gun shortly before he was arrested and he was not searched before he was placed in the rear of the van.

Mrs Plum claims the state owed Mr Plum a duty of care to take "reasonable precautions against him suffering injury" and that it owed her a duty of care to "take reasonable care not to cause her mental harm".

NSW Police deny that they owed Mr Plum a duty of care or that they breached any duty. They also say Mr Plum himself was partly responsible under the legal principle of contributory negligence.

It asked the case be moved to the NSW Supreme Court because the case would examine complex issues of whether police have a duty of care and the scope and content of such duty. Further, it argued the principles are a matter of "public importance".

However the Supreme Court has ruled the case should be heard in the District Court and will hold a 10-day hearing in February.

At an inquest in November 2012, deputy state coroner Hugh Dillon was told Mr Plum's arrest was difficult because he attempted to escape, resisted arrest when caught and because "he was a large, determined and powerful man" who was trained in martial arts.

The arresting officers did not frisk him, partly because they had such difficulty getting him under control. They decided to put him in the truck and search him when they arrived at the police station, three minutes drive away.

On arrival, Mr Plum refused to get out and then produced a pistol and shot himself.

Mr Dillon concluded it would have been "prudent" to search Mr Plum before he was handcuffed and placed in the truck. "It is likely that, had he been searched before being placed in the back of the truck, Mr Plum's death would probably have been prevented."

In findings handed down in May 2013 Mr Dillon recommended a number of changes to police practice and procedure. He said officers should search all people taken into custody before putting them inside a police car or truck, "unless there is sound reasons not to do so". A spokesman for NSW Police said this recommendation had been implemented.

Mr Dillon also recommended the rollout of CCTV in caged vehicles be expedited. A spokesman for NSW Police said there is no plan to rollout CCTV in caged wagons at this point in time.

Mr Plum had a history of mental illness and an extensive criminal history. At the time of his arrest the police computer system COPS had recorded warnings that caution should be taken when dealing with him. This included a warning he might be carrying a weapon.

Ms McLoon had found the small revolver and bullets in the motel room Mr Plum was staying in but didn't tell police when they arrived and was generally unco-operative, the inquest heard. Mr Dillon also found it was likely Ms McLoon told Mrs Plum about the gun and the two women searched the motel room for it. Mrs Plum denied this.

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