Melanie was sitting behind the front-seat passenger in a parked Nissan Almera on Brookview Way in Tallaght, south-west Dublin, when gunmen pulled up beside the car in a 4x4 and fired two shots into it.
Gardaí suspect the gunmen had intended to shoot at either her boyfriend, Christopher Moran, who was in the front passenger seat, or another friend who was driving the car.
It appears the shots were fired through the back window.
“We’re not sure did the car move and the jeep tried to keep up or the gunmen got nervous or what and missed the target,” said a Garda source.
“The window didn’t fully shatter — the gun was right up against the glass.”
Gardaí said people from the 4x4 had earlier been throwing stones at a house on Brookview Way, where the driver of the Almera, his brother and their family lived.
Local sources said this had been going on for around an hour. It appears people in the house rang the man who was driving the car and that Christopher and Melanie decided to go over too.
One source said a brother of the driver got into their car when it arrived, but that another family member took him out of the car a minute later.
A number of people said the Almera was only there a couple of minutes when the shots were fired.
Meanwhile, gardaí are making progress in their hunt for the killers.
This has been aided by the way the gunmen abandoned their getaway car intact and dropped the suspected murder weapon, balaclavas and gloves.
They drove a short distance to Citywest and left the 4x4 near Browns Barn, off the Naas Rd.
Experts also found two spent cartridges in the jeep, which will be subject to ballistic examination.
Gardaí have also retrieved a “clear image” from CCTV in the area of one of the gunmen as they abandoned the car.
“Ideally, we won’t want to arrest him until a picture has been built up on his background — we want to be able to ask him questions,” said a garda source.
Gardaí suspect the gun attack was in revenge for the murder of Stephen O’Halloran in Tallaght in Jan 2009.