The daughter of a notorious US serial killer has offered her DNA to gardai in a bid to help solve cold case murders that took place during a period when her father visited Ireland.

Jenn Carson, whose father was Michael 'Bear' Carson, also known as the 'San Francisco Witch Killer' spoke to Dave Fanning on RTE Radio 1's Ryan Tubridy Show today.

Michal Carson, along with his second wife Suzan, were convicted in 1984 of three brutal murders in California but they are suspects in almost a dozen other murders both in the US and in Europe in the late 1970s and early 1980s.

The pair travelled to Europe in the late 1970s and visited Ireland in 1978 and 1979 and Jenn Carson has offered to give her DNA to gardai in a bid to solve cold case murders in Ireland in that period.

"I don't think I can solve these cold cases but I have offered to give my DNA to any cold cases. I know that you have four cold cases in Ireland within the time period and one of them is a little bit similar to the modus operandi so I would be glad to give my DNA to your police in Ireland or other European or US forces during the 1978 to 1983 period.

Jenn told Dave Fanning that the father she grew up with was a "caring, hippie, stay-at-home dad" but after he met Suzan he changed.

"There was the obsessive relationship between the two, there was extremist beliefs and there was the dropping of acid, not experimentally but every day they were using LSD which I think caused some brain damage. I truly believe both people had psychopathic tendencies where they did not feel empathy and they did not feel remorse."

While police pursued them they discovered a manifesto left behind the pair in 1982 called 'Cry for War' which called for all witches to be killed as well as plans to kill US President Ronald Reagan.

The pair were eventually arrested in 1983 and both were sentenced a year later to 75 years to life behind bars.

Jenn Carson now works with the children of prisoners, to help them cope with the loss of a parent in these circumstances.

She also told Dave Fanning about her last visit with her father in prison.

"I went to see him as a young adult to say goodbye and confront him. There was absolutely no remorse. My father was not in there any more, that it was a different person and I walked away."

Online Editors