A 12-page note was discovered on the body of a man who was found dead alongside his brother and dad on a farm, it has tragically emerged.

Gardai (Irish Police) are investigating the suspected murder-suicide, and the possibility that the killing of Mark O'Sullivan, 26, may have been planned by his brother and father beforehand.

Mark was found dead in his bedroom in Kanturk early on Monday morning, having died from gunshot woods, reports the Irish Mirror.

Gardai are still piecing together the sequence of events that ended in bloodshed at the remote farm in Kanturk, Co Cork.

Two autopsies were conducted on Tuesday to try to establish how 59-year-old Tadgh O’Sullivan and his sons Mark and 23-year-old Diarmuid lost their lives.

Gardai outside a farm in Assolas, Kanturk, north-east Co Cork, where the bodies of Tadgh O'Sullivan, and his two sons, Diarmuid and Mark, were found

And it has now emerged that a lengthy note was discovered on the body of Diarmuid O'Sullivan, who was found dead in a nearby field alongside his father Tadgh.

Irish Times reports that the note was strapped to Diarmuid’s thigh and suggested that both Diarmuid and his father had been planning to shoot Mark over a grievance that they had regarding a proposed will dividing up the family’s 115-acre farm.

The apparent note has been described as lengthy and detailed.

The mother who lost two sons and her husband in the horror incident has been left “absolutely devastated”.

Father John Magner prayed with Ann O’Sullivan after the bodies of Tadgh, Mark and Diarmuid were found on the family farm in Co Cork.

Diarmuid O'Sullivan was found dead along with his brother Mark and his father Tadgh

He said: “There are no words.”

A third postmortem will be held today as the Garda probe continues.

Fr Magner said the community has been left “numbed, stunned and devastated”.

It’s understood Mark died first in an upstairs bedroom of the family farmhouse.

Mechanic Tadgh and younger son Diarmuid sustained fatal gunshot wounds in a field 600 metres away.

Gardai recovered three legally held shotguns and rifles at the scene.

The incident is being treated as a suspected murder-suicide

It’s believed there had been a simmering row about land and inheritance between the three.

However, gardai last night dismissed reports they had called to the O’Sullivan home previously in relation to any altercation.

A spokesman confirmed two postmortems were completed yesterday with a third scheduled for today.

He said: “A formal identification of the three men will follow thereafter.

“Contrary to some reports in the media, there had been no Garda interaction with the deceased men, or their family, prior to the tragic events of October 26, 2020.”

The boys' mum Ann has been left “absolutely devastated”

At a local Mass on Tuesday, prayers were said for the family and Mrs O’Sullivan.

Fr Magner met the 60-year-old after attending the scene and praying for the three men.

He said the wife and mother was “absolutely devastated” and that he prayed with her for the strength to cope with her “immense loss”.

He told RTE: “You cannot put words into how she felt.”

Fr Magner added it was also devastating for family and friends.

He said: “To find that friends they have are just gone, departing this world so early in life.

“It’s awful for families too when people pass away very young. It’s very tough on people.

“It’s very difficult for younger people to understand why all these things happen.”

Fr Toby Bluitt, parish priest of Kanturk and Lismire and administrator of Castlemagner Park, told how the community was “in deep shock and numbed”.

He said that, on behalf of the communities of Castlemagner and Kanturk and Lismire, “we offer our deepest sympathies to Ann O’Sullivan on the tragic loss of her husband Tadgh and sons Diarmuid and Mark”.

The parish priest added: “All of us are in deep shock and numbed by this heart-breaking news. We pray the Lord’s consolation for Ann and her family and for God’s mercy for Tadgh, Diarmuid and Mark. May they rest in peace.”