It was one of the great mysteries of the twentieth century. Lord Lucan vanished 40 years ago this month after apparently bludgeoning the nanny of his children to death in London.
The playboy peer, once considered for the role of James Bond, is now assumed to be dead, but his remaining Irish tenants have continued to pay thousands of euro to his estate in ground rents.
At one time, Lord Lucan's family owned over 60,000 acres in Co Mayo, and they lived in a grand mansion next to the barracks on the edge of Castlebar.
One of Lucan's ancestors, the infamous third Earl, was so cruel to his tenants that he was known in the locality as "the exterminator".
The stately home is now part of St Joseph's secondary school in the town, and girls go to classes in the old ballroom, where the Lucans lived it up at their parties a century ago.
The family has left imposing buildings and there is a Lucan Street in the town centre, but the only living remnants of the notorious dynasty in Castlebar are the trees near the old house and along the Mall, which used to be the lord's cricket pitch.
The Lucans may be long gone, but Castlebar continues to be a money-spinner for the vanished aristocrat's family.
Under old rules of tenancy, the Lucan estate owns the freehold for a large number of Castlebar properties, many of them in the centre of town. The arrangement is supposed to last for 999 years. Small amounts of ground rents are due on these properties every year, but it all mounts up when the bills go unpaid.
When the Eton-educated 7th earl, who is only thought to have visited Mayo once, sensationally disappeared in November 1974 after the bloody scene at the family home at Lower Belgrave St, it was hoped locally that the Irish tenants' financial obligations to him might have vanished also.
But the Lucan estate continued to ask for the ground rents, and many local people, including the Taoiseach Enda Kenny, have done deals with the landlords to clear these payments with significant lump sums.
Like many residents in Castlebar Frank Durcan, a well-known local auctioneer and councillor, grew up in a house in the centre of Castlebar with ground rents owed to Lord Lucan.
Meanwhile, the free-spending peer and absentee landlord was living it up over in London, and seemed to occupy most of his time as a professional gambler at the Clermont Club.
There is only one account of him visiting Mayo. He is thought to have dropped in at the local school with his mother in the 1950s. Students were lined up to welcome the aristocrats and they were greeted with flowers.
Frank Durcan said of the ground rents, which have cropped up as an issue over the decades: "We never paid them and I don't think most people in Castlebar have ever paid them.
"But it does become an issue when you are buying or selling property. Solicitors insist that the ground rents are sorted out."
Many property owners in Castlebar have chosen to buy out the leases, and this has proved to be lucrative for the estate of the absentee landlord.
Frank Durcan said he bought the house next to his in 2007, and the freehold was owned by the Lucan estate.
"In order to buy out the ground rents, I had to pay the estate €952.
Even the Taoiseach Enda Kenny has had to pay over money to the Lucan estate. Some years ago he did a deal to buy out the ground rent on his constituency office in Castlebar.
There are numerous similar stories of payouts to the Lucan estate in recent decades.
At the guesthouse where I stayed on Lucan Street in Castlebar this week, the owner Raymond Kenny (no relation of the Taoiseach) told me he had paid €600 to buy out the ground rent 20 years ago.
The local Castlebar historian and literacy campaigner Ernie Sweeney believes Lord Lucan is the Loch Ness monster of Castlebar, and every so often his name comes up in the headlines. Mr Sweeney himself has a strong link to the Lucan family.
His great grandmother worked as a housekeeper for the Lucans, and he grew up with stories of one of the lords pedalling around Castlebar on a tricycle.
He told Weekend Review there is even some local folklore suggesting that he himself may be related to the Lucans, as a result of an "Upstairs Downstairs" tryst.
"Some people in the town believe I am related to the Lucan family, and others don't," he says somewhat coyly.
The family may have gone, but they are still part of local legend, with stories of a ghost of one of the lords haunting the local bacon factory in years gone by, and a curse placed on the family by an old woman evicted by Lord Lucan's agents.
The third Earl, who spent many years living in Castlebar in the 19th century, was just as notorious as the peer who vanished in the 1970s.
Declaring that he would not "breed paupers to pay priests", he evicted thousands of tenants during the famine.
According to the Dictionary of Irish Biography, he was greatly feared by his tenantry. On one occasion, believing him to be away, they burned his effigy in Castlebar.
"(They) scattered in terror as Lucan galloped into their midst on his great black horse, shouting 'I'll evict the lot of you!' "
Lucan's infamy followed him onto the battlefield. In 1854, in Crimea, he gave the order for the most ill-starred military manoeuvre in British history - the Charge of the Light Brigade.
With this historical baggage, it is surprising that Castlebar has not made more of its link, with a Lord Lucan festival.
Although his family collects whatever ground rents they can, the vanished lord's son George Bingham is only believed to have turned up in Castlebar once.
In 1997, he went for a drink incognito in a local pub. He said afterwards: "It's much bigger than I imagined...I was a bit nervous and sort of sneaked into town. Nobody knew who I was."
The local TD, one Enda Kenny, suggested that there would have been no animosity towards him. Enda told a Fleet Street reporter: "I wish I had known he was coming - I would have bought him a drink."