The sun was shining in Kenmare this week as tourists sipped coffees outside restaurants and browsed stalls around the town’s square.

All seemed oblivious to the drama unfolding in the hills above this picturesque town in south Kerry.

For locals, it was different. The mood has turned sombre lately as one subject dominates conversations: the macabre details of the apparent violent death met by 56-year-old local man Michael Gaine on his hillside farm, less than 6km from Kenmare.

Gaine’s farm lies just off the popular tourist Ring of Kerry route that wends between peaks and valleys.

“It’s been the talk of the place since Mike disappeared two months ago and since we heard the news at the weekend, people are in an awful state altogether,” said one man, shaking his head. “It doesn’t bear thinking about – it’s beyond belief.”

The details, when they emerged last weekend, shocked locals.

Gaine’s nephew, Mark O’Regan, was spreading slurry on his uncle’s farm with a local agricultural contractor when they noticed that the slurry tanker was not working properly.

They went to examine the trailing chute at the rear of the machine and found it blocked. When they examined it closely, they discovered the obstruction was caused by human remains. They immediately notified gardaí who quickly arrived on the scene.

Defence Forces personnel join the search for Michael 'Mike' Gaine near Kenmare in Co Kerry. Photograph: Noel Sweeney/PA Wire

After almost two months of fruitless searching, involving scores of gardaí, mountain search teams and Defence Forces personnel, this was the first significant clue to explaining what had happened to Gaine, who had disappeared in March.

A native of Kenmare, Gaine had grown up on Railway Road in the town with his parents, James and Sheila and his younger sisters, Noreen and Catherine. The family originally came from Carrig East, midway between Kenmare and Moll’s Gap, a scenic pass between the town and Killarney.

The Gaines have been farming around Kenmare for generations – the 1911 census shows there were 49 Gaines in the town, the vast majority farmers or cattle dealers from nearby hillside areas such as Carrig, Carhoomeengar and Lissyclerig.

Gaine attended Kenmare National School and after completing his secondary education at Kenmare Vocational School, he worked in construction for a period before being employed as a fencing contractor. He helped his mother Sheila at the farm after his father James died in 2003.

By then, Gaine had met his future wife Janice at a ball in Killarney. The couple had travelled to Australia and New Zealand before they settled down at an architect-designed house they had built on their land at Carhoomeengar East in the late 1990s.

Gaine used to make the short journey from his home to Carhoomeengar East to Carrig to help his mother Sheila on the farm but he ran the farm himself when she could no longer manage. She died in a nursing home in Kenmare on February 1st.

Excavations on the farm of Michael Gaine near Kenmare in Co Kerry. Photograph: Noel Sweeney/PA Wire

It was just two weeks after the month’s mind memorial mass for his mother that Gaine disappeared. He was last seen on CCTV footage, buying mobile phone credit at Whyte’s Centra in Kenmare at 9.48am on March 20th before driving off in his bronze-coloured 10-year-old Toyota Rav 4.

When he failed to return home that evening and did not answer his phone, Janice contacted her sister-in-law Catherine. Catherine’s husband Sean O’Regan, a garda in Kenmare, reported Gaine missing to gardaí on Friday, March 21st, triggering a missing persons investigation.

That day, friends and family began searching the farmyard at Carrig East. It was here that gardaí found Gaine’s wallet and mobile phone in his car. Up to 200 volunteers joined the search on Saturday and Sunday to comb the 1,000 acres of hillside around the farm.

Gardaí quickly established there had been no activity on Gaine’s bank accounts and an examination of his mobile phone showed a number of missed calls but no outgoing calls or texts after the last sighting of him at Centra.

On March 24th, members of Kerry County Fire Service assisted gardaí in carrying out a search of the slurry tank under the 20-metre slatted unit where Gaine had kept his 40 suckler Limousin and Charolais cows. Those, along with 500 sheep, earned Gaine his income from the farm.

The Garda Press Office issued a series of statements in relation to the search for Gaine, which was still, at this point, a missing persons investigation. No statement made specific references to the 50,000-gallon slurry tank being searched; the Garda said simply: “Searches have been carried out at Michael’s farm.”

Media reports said searches of the slurry tank took place on March 24th – four days after Gaine went missing – and one Garda source told The Irish Times the tank’s main chamber was drained fully, and the slurry in a second smaller chamber was then filtered into the main chamber.

But no human remains were detected.

Missing Co Kerry farmer Michael Gaine: body parts were found in a slurry tank on his farm.

One local told The Irish Times that the main tank was drained of liquid and that up to a half a metre of solids remained.

Members of the fire service wearing breathing apparatus then waded through the solids, prodding them with poles. But, again, they detected no remains.

Events took a grim twist last weekend when Gaine’s nephew and the agricultural contractor emptied the remaining slurry from the tank and spread it on a number of fields near the farm.

By then, the investigation had been upgraded to a murder inquiry. The change in status came just a day before Gaine’s wife and his sister Catherine made a video appeal on April 30th for any information about what happened to their husband and brother.

“We just want to Michael to come home – we want to know what happened to him because if we can’t find Michael, I just don’t know what I am going to do,” said Janice.

She said her husband’s disappearance was “totally out of character”.

Garda sources say the decision to upgrade the investigation to a murder inquiry came after exhausting all possibilities that some accident had befallen Gaine or that he had self-harmed given that surface searches of the farm had yielded no trace of him.

Locals say they believed from the beginning that Gaine had been the victim of foul play and was most likely disposed of in the slurry tank. Sources close to gardaí say they, as much as anyone else, were shocked by the manner in which Gaine’s remains were discovered.

“They searched the slurry tanks thinking they were looking for a body – they never thought that Mike Gaine would be cut into pieces and dumped into the tank; they never thought they were dealing with that level of barbarity,” said one source with an insight into the Garda’s approach.

Gardaí believe Gaine was murdered by a person known to him soon after he arrived at the farmyard at Carrig on the morning of March 20th and that his killer dismembered his body in the slatted unit before disposing of the body parts in the underlying slurry tank.

A chainsaw was discovered hidden in the farmyard and brought to Forensic Science Ireland’s laboratory in Dublin for examination to see if any DNA evidence could be obtained.

Gardaí arrested a man in his 50s last Sunday in Tralee and questioned him for up to 24 hours before releasing him without charge.

The Garda Press Office statement issued on his release made no mention of a file being sent to the Director of Public Prosecutions (DPP), suggesting that gardaí face a challenge in making any case against the man.

Back in Kenmare, nobody is willing to speak publicly about the Garda investigation to date. Privately, people are angry and few hold out any hope of Gaine’s killer being brought to justice for a crime that has left many stunned and numbed.

One local, who did not want to be named, said: “This is gruesome – it’s the sort of things the drug cartels do … When people saw the markers in the fields where they found parts of Mike, they were shocked.”

The local said people in the area were “raging over the handling of it all by the gardaí”.

People were wondering why the Garda inquiry was not “declared a murder investigation sooner” and asking why the slurry tank was not emptied and searched properly, they said.

“They would have found out what happened Mike much sooner. They are saying if that was done eight weeks ago, we would be in a totally different situation now – the guards would have had much better physical evidence to put to the suspect when they arrested him,” the local said.

“Instead, it looks like they are facing an uphill battle to get justice for Mike.”