A SOUTH Dublin businessman suspected of murdering Elaine O’Hara was in garda custody tonight.
Detectives swooped on the married man at a house in Foxrock early this morning.
The 41-year-old father-of-two was being quizzed at Blackrock Garda Station in connection with Elaine's murder.
Murder detectives have until tomorrow to charge or release the father-of-two being questioned in connection with the killing.
Gardai can question him until tomorrow afternoon at the latest.
The 36-year-old went missing on August 22 last year. Her remains were found over a year later by a woman walking in the Dublin Mountains.
A senior source described today’s arrest as a “major breakthrough”.
“This is a highly significant development. It is believed that this man met Elaine several times before she died,” the source explained.
It's believed that he had been in frequent contact with the childcare worker before her disappearance on August 12, 2012.
The Herald has learned that the suspect had been getting medical treatment in recent weeks which stalled today’s arrest.
Sources say he has led quite an extravagant personal lifestyle and is a “man of some means”.
It is understood that he was very shocked when arrested during a “dawn raid” at his home.
Evidence of his contact with Elaine was gleaned from the murdered woman's mobile phone and computer in the days after her remains were found.
A search of his house has been taking place today, and it is understood a number of items have been removed - including mobile phones and a computer.
The man is being held under Section 4 of the Criminal Justice Act 1984 which means he can be questioned for up to 24 hours.
He has no previous convictions, and has not previously come to the attention of gardai.
The details surrounding Elaine's death shocked the nation as they began to emerge last month. What started as a missing person's case soon became one of the biggest murder investigations in years.
Elaine's remains were discovered by a woman walking her dog in a wooded area in Kilakee, on the foot of the Dublin Mountains in Rathfarnham, on Friday, September 13.
Just days earlier a number of items belonging to Elaine were discovered in a reservoir in Roundwood.
Gardai were later able to confirm that these items belonged to the tragic woman – who may have died during a violent sex game.
The find, which included a Dunne Stores key fob and items of an extremely sexual nature, sparked the murder probe.
Elaine was last seen at Shanganagh cemetery in Shankill on August 22 last year.
Her green Fiat Punto was found at the cemetery two days later.
It is believed she visited her mother's grave on the evening of her disappearance and her family had not heard from her since.
She was described as 5ft 4in in height and of stocky build with mousey brown hair. When she went missing gardai say she was wearing jeans, runners and
a blue top, with either a jacket or a jumper.
Her remains were not buried but had sunk into the ground as her body decomposed