Two young men were killed today as they sped the wrong way down one of the country's busiest roads causing a head-on crash which left an off-duty garda seriously injured.
The officer was driving home after finishing work when the car the pair were travelling in ploughed into his vehicle just after 6am on the N7 Naas Road near Dublin.
It is the second fatal car crash the garda has been involved in this year after a teenage chess player was knocked down early on New Year's Day.
The officer is likely to be cleared of any blame for the January accident and is not at fault for the latest crash.
The Garda Ombudsman initially took over the investigation but handed it back to the gardai after establishing the two men, aged 19 and 20, had travelled the wrong way down the motorway.
"This decision follows a technical and forensic examination of the scene as well as independent witness accounts," an Ombudsman spokesman said.
The men were in their Fiat Punto hatchback when they turned the wrong way down a slip road on to the N7 near Citywest travelling 400m on the southbound side before crashing head-on into the garda's car.
A spokeswoman for Tallaght Hospital said the garda, aged in his late 20s, suffered serious injuries in the crash.
The garda was being investigated over the car accident which claimed the life of Philip Hogarty, from Tallaght, south Dublin.
He was knocked down as he made his way home from celebrating the New Year after stepping over bollards marking road works on the Blessington Road.
Eight people have been killed in the last three days and so far this year 63 people have died on the country's roads.
A team from the Ombudsman's office spent several hours at the scene near Citywest along with gardai as the investigation got under way.
Traffic was diverted for several hours with severe hold-ups until mid-afternoon when the N7 reopened.
Six people were killed in a series of crashes elsewhere, including three young men from Co Cork who died when their car went into the sea at a beauty spot near Castletownbere.
They were Shane Kelly, 20, from Cluin, Allihies, Castletownbere, Colum Harrington, 21, from Ferrylodge, Bere Island, and 17-year-old Fintan O'Driscoll, from Foildarrig, Castletownbere.
Gardai said they had yet to establish how the car ended in the sea but it is believed the car's mud-covered wheels lost grip and slid across a grass embankment.
Meanwhile, a mother and her child were in a stable condition in hospital after a crash which claimed the lives of her two other children.
The woman was driving her three youngsters along a country road near Nurney in rural Kildare on Friday morning when the car collided with a lorry.
A seven-year-old boy was killed, his eight-year-old sister died later and their mother and her other child were left fighting for their lives.
A 34-year-old woman was killed when the car she was driving crashed on a notorious stretch of road near Murrintown, Co Wexford on Friday evening.