A YOUNG rugby star, his brother and their father who died in a farming tragedy in Northern Ireland may have been trying to rescue a dog, it has emerged.

Investigators are still trying to determine the exact circumstances of the accident in Co Down, which is believed to have unfolded after one of the men fell into a slurry tank at the family's farm in Hillsborough.

Ulster Rugby star Nevin Spence, 22, was killed along with his 30-year-old brother Graham, who is married with two children, and their father Noel, 52.

A third sibling, Emma, a well-known artist, was taken to Belfast's Royal Victoria Hospital for treatment for the inhalation of fumes and her condition is described as stable.

There is widespread shock at the devastating blow to the remaining family members – the young men's mother Esme and their sister Laura.

Emergency services attended the farm in Drumlough Road outside the Co Down village after 6pm on Saturday following reports four people had fallen into the slurry pit.

Investigations into the cause of the tragedy are ongoing, amid unconfirmed reports that the family members were trying to save one another, and that the tragedy may have been sparked by efforts to save a dog from the slurry tank.

The Health and Safety Executive for Northern Ireland (HSENI) is to investigate the circumstances in an effort to establish a clear picture of how the events unfolded.

A spokesman said: "From HSENI's initial investigations, it appears that the three family members who entered an underground slurry tank died from the effects of exposure to slurry gases. The exact sequence of events is not yet clear, but HSENI is investigating a definite line of enquiry."

Nevin Spence was a star of the Ulster Rugby team and was tipped to have a glittering international career ahead of him.

At Ulster's home stadium of Ravenhill in Belfast, his former colleagues were visibly shaken.

Chief executive of Ulster Rugby Shane Logan said: "I am deeply saddened by this tragic news. Nevin was a wonderful player but also a wonderful person. He was well-liked by everyone and his loss will be deeply felt by his team-mates and everyone at Ulster Rugby.

"He will be sorely missed and the thoughts of everyone involved in the game are with his family at this time."

Sports stars, fans of the young rugby player and friends of the family have paid tribute to Nevin and his relatives, and floral tributes were yesterday left outside Ravenhill.

Northern Ireland First Minister Peter Robinson and deputy First Minister Martin McGuinness said they were deeply saddened by the accident. The Ministers said: "This tragedy has shocked the entire community and is a terrible reminder of the dangers of farming life.

"Nevin was a rising star of local rugby and it is only a matter of months ago, in happier times, that we had the honour of hosting him and his colleagues at a reception in Parliament Buildings to celebrate the achievement of Ulster in reaching the Heineken Cup final.

"His untimely death is a blow for the game in the province and we sympathise with his teammates and everyone at Ulster Rugby, who have lost a true colleague and friend."