READ MORE- Annie McCarrick: American missing in Ireland since '93

READ MORE- Serial rapist release haunts Annie McCarrick friend

A cold case expert believes that Annie McCarrick may have gone on a secret date on the night the Long Island woman disappeared.

The Irish-American has been missing for 18 years after she vanished without a trace on March 26, 1993.

The last confirmed sighting of the 26-year-old was in Enniskerry, just east of the Wicklow Mountains. She had left her Dublin apartment earlier that day to spend the day exploring the countryside.

Later that evening there were unconfirmed sightings of a woman matching her description at Johnnie Fox’s Pub in Enniskerry, with a man in his twenties.

In a new television series by the Irish channel TV3, Crime in Mind, Dr Mike Berry, a forensic psychologist re-examines the case and determines that Annie’s actions that day, determine she was going on a mystery date.

"We can assume she's gone to meet a man for a date at 5pm and she wants to hide him for a while," he said.

"There is a reason why she is hiding it.

"Maybe it is a new relationship or one she was uncertain about.

"If we are on the right line, she's gone over to meet someone and she's ended up in Johnnie Fox's and from there afterwards it's all gone pear-shaped for her.

"She wasn't killed for money or for political reasons. The reasons why people kill are jealousy, anger or sex.

"At best she could have been walking with the person and fallen down and had an accident and he panicked and dumped the body.

"It's more likely she resisted his sexual advances and he lost his temper and killed her. He may not have intended to kill her.

"It would appear that she would have known him. That puts him in a much weaker position.

"He doesn't know if she has mentioned anything about him and that makes me suggest that she was hiding his identity."

Born and raised in Long Island, New York, Annie moved to Ireland in 1987. She studied teaching at St Patrick’s Training College in Drumcondra and later at the National University of Ireland in Maynooth.

She returned home to the U.S. in 1990 but decided to move back to Ireland in 1993.

In the five years following the disappearance of the American woman, another five woman went missing in the east Leinster area.

In response to this, Operation Trace was established in 1998 to investigate whether the disappearances could be related. The leading suspect in the operation was the convicted rapist Larry Murphy.

According to Dr Mike Berry, Murphy matched the criteria for the likely killer.

"He has some of the characteristics of the likely killer," he said.

"But then, this is the key point, there are other people in the country that have the same characteristics," he added.

READ MORE- Annie McCarrick: American missing in Ireland since '93

READ MORE- Serial rapist release haunts Annie McCarrick friend