The Penyffordd Farm haunting ("Brother Doli"), Treuddyn

Penyffordd Farm stands in remote countryside at Treuddyn, near Mold in Flintshire, north Wales. Nobody agrees on its age. BBC publicity called it 15th century. Others say 17th century, and a date stone reads 1610. Nearby ran the old pilgrimage route from Shrewsbury to Holywell.

In February 1997 David and Rose-Mary Gower moved in with their family. David was a teacher and a chemistry graduate. Rose-Mary said poltergeist activity had touched her own family's home in Guernsey, before and after she was born. Leaning against the farmhouse wall they found a gravestone. It named Jane Jones, aged 15. The year was 1778. Before a daughter's wedding garden party, they moved it to a secluded spot.

What followed lasted years. Stains and carvings appeared inside and outside the house. Around 200 of them. Religious images. Welsh words. Tangnefedd, peace. Mynach, monk. Gobaith, hope. Cariad, love. The name Jane. And "Help me!" Some appeared, then disappeared. Welsh religious words even turned up in emails and printed documents.

There were footsteps and lifting latches. Children singing, briefly. Candles and incense on the air. Sudden changes in temperature. Pools of water. John-Paul, the Gowers' adopted son, saw a monk-like figure most often. A male voice was heard answering him in Welsh.

In 2002 their daughter Nicolette woke in the night. "One night I awoke and saw a figure standing over the cot," she said. "It was leaning over looking into the cot where Quinn was sleeping… It had a hood, like a habit a monk would wear." Others saw a hooded figure walk past the house. Rose-Mary saw a girl in the garden, cloaked and mournful, heavily pregnant and in old fashioned clothes. The family's story was that Jane had died in childbirth, unmarried, and been buried in the garden rather than consecrated ground. They called the presence Brother Doli.

In October 2000 the parapsychologist Dr Michael Daniels began investigating for the Society for Psychical Research. He visited 14 times. He catalogued and photographed the markings and set time-lapse video on one wall. He never witnessed anything anomalous. On the night a carving appeared, the video failed. His paper in the Journal of the Society for Psychical Research in 2002 said an elaborate hoax "could not be ruled out". Perhaps a mixed case, real phenomena with deliberate embellishment. Yet he told the press: "It was a spectacular case. There were actual physical things in the house that could be observed."

David Gower admitted the accounts had changed in the retelling "to make better stories". A chemist suggested words written in salt water, then painted with silver nitrate, which shows up in light. Psychologist Malcolm Schofield proposed a priming effect. Some Welsh words were misspelled, and the gravestone was in English. Tom Ruffles faulted Daniels for never interviewing outside witnesses. Michael Levy, who bought the farm in August 2012, reported "a grand total of zero" ghostly events. Rose-Mary later wrote that the activity ceased abruptly in January 2008.

In August 2023 BBC Three and BBC Wales returned to the farm with Paranormal: The Girl, The Ghost and The Gravestone, presented by Sian Eleri. Four episodes. Daniels, the family, a genealogist and the new owner. And the old question. Paranormal, or all a hoax?