British police believed he was an Irishman, and Irishmen were arrested in connection with his gruesome deeds in northern England in the 1970s and early '80s – but just how Irish was the Yorkshire Ripper?

The Irish connections of serial killer Peter Sutcliffe are to be examined in an upcoming documentary on RTé television as part of the CSI Fada series.

Presenter Garry MacDonncha told the Sunday Tribune: "To make the programme we visited Leeds and spoke to the Irish community about the search for the Yorkshire Ripper and how it affected them. Every Irishman was a suspect as the police visited Irish clubs. We spoke to one Irishman who was arrested three times because he had a moustache."

British police at the time acted on reports – from would-be victims who had managed to fight him off – that the Ripper had an Irish accent.

"Some of the women [murder victims] had been found to have traces of oil on them from the hammers and screwdrivers their attacker used. Sutcliffe was a lorry driver but at the time the police suspected the Yorkshire Ripper was an Irishman who worked on the roads with tarmac," said MacDonncha.

Even after Bradford-born Sutcliffe was arrested for the murders in January 1981, the Irish link continued with the UK press claiming the Yorkshire Ripper's mother, Kathleen Coonan, hailed from Connemara.

"We did a bit of digging through marriage and birth certs but it was actually Sutcliffe's great grandfather, Edward Coonan, who was Irish born. He came over from Tipperary in the 1860s. We did track down his branch of the Coonans to around Ardcroney and Cloughjordan in Tipperary. I don't know if there are any Coonans living there now – if so, they could be related to Peter Sutcliffe."

Sutcliffe himself, now 63, and on the 28th year of a 30-year prison sentence for 13 murders, seems to have become more aware of his Irish roots in recent years. He changed his name by deed poll to Peter Coonan in 2001.

But MacDonncha thinks this is more linked to his future hopes of getting parole than a love of Ireland.

"He can apply for parole next year but the British prime minister Gordon Brown has hinted he won't release him while he's in power. That's why there's talk Sutcliffe may apply to the European Court of Human Rights. Possibly he thinks they might be more favourably disposed towards a Peter Coonan than a Peter Sutcliffe with all the baggage that name has."

'CSI Fada: The Irish Ripper' airs on RTé1 on Monday 12 October at 7.30pm