Profile: Thomas Martens
Thomas Michael Martens (67) set up home in Tennessee in the United States to raise his four children with his wife Sharon.
The Martens's home was in Knoxville, eastern Tennessee, as close to Charlotte in North Carolina as it is to the state's most famous city, Nashville.
With his wife, Mr Martens has three sons Bobby, Connor and Stewart, as well as a single daughter, Molly. He also became very close to his brother-in-law Michael Earnest.
For more than 30 years, he worked as an agent for the FBI, one of the most respected law enforcement roles in the US.
He had to mandatorily retire after 31 years' service more than a decade ago.
Mr Martens had qualified as a lawyer, having attended a prestigious Georgia college.
However, he never practiced as a lawyer and instead focused his legal skills on his work with the FBI. He was only briefly a field agent, based in Miami, Florida, when the state faced a crisis over the activities of drug gangs.
On his retirement from the FBI in the late 2000s, he got a job with the US Department of Energy. He worked in the counter-intelligence unit based at Oak Ridge in Tennessee.
Mr Martens, a staunch family man, was a keen golfer. He only drank moderately, usually having a single glass of wine with a meal.
In 2008, his daughter decided to move to Ireland to work as a nanny. By 2010, the Martens family were aware she was now in a relationship with Jason Corbett, the father-of-two who had lost his wife to an asthma attack in 2006 and whose children Molly had travelled to Limerick to care for.
Mr Corbett was eight years Molly's senior.
The family were delighted with Molly's new-found happiness and Mr Martens walked his daughter down the aisle at historic Bleak House in Tennessee on her wedding day on June 4, 2011. The family were even more delighted with the decision by Molly and Jason to relocate their family to Davidson County in North Carolina - a four-hour drive away.
Given the distance, Mr Martens and his wife were frequent visitors to the home their daughter and son-in-law had set up at Panther Creek in the Meadowlands, roughly midway between Lexington and Winston-Salem.
Mr Martens considered Jason's children Jack and Sarah to be his grandchildren.
However, the 2011 wedding marked the first deterioration in the relationship between Mr Martens, his son-in-law and Jason's Irish family. Mr Martens admitted he disliked and had disdain for Jason because of the level of drinking, rowdy behaviour and the way his home was treated during a pre-wedding party.
Eventually, Mr Martens disliked his son-in-law to the point where he actively encouraged his daughter to divorce the Irishman.
Mr Martens said that, when with Jason, he "made nice" and worked to have a superficial relationship with him.
"He was not my favourite person," Mr Martens said.