Even by the recent grim standards of the Province, the cold-blooded shooting of the teenager as she lay sleeping at the home of her Protestant boyfriend has shocked many nationalists and unionists alike.
Although the Loyalist Volunteer Force was quick to deny responsibility for Tuesday's killing, police are almost certain it was a sectarian attack, possibly motivated by sheer hatred of a Catholic young woman with a Protestant boyfriend.
If the LVF's denial is to be taken at face value, it could mean the shooting was carried out by a "freelance" loyalist or group of loyalists.
Two men, described as local, arrested in connection with the murder were still being questioned by police yesterday.
Today's service will be held at St Anthony's Catholic church in Bernadette's home town of Craigavon, Co Armagah, where she lived on one of the mixed estates in the area. A few miles away is the staunchly loyalist village of Aghalee, where the teenager had been staying with the family of her boyfriend, Gordon Green.
The young couple had been up late with Gordon's sister, Wendy, and the three had fallen asleep fully clothed in an upstairs bedroom.
As Bernadette and her boyfriend slept in each other's arms, a gunman entered the house through an unlocked back door, crept up the stairs and shot her in the head four times. She died in hospital 12 hours later.
Bernadette and 19-year-old Gordon had been together for nearly a year, after meeting at the food processing company where they both worked in nearby Lurgan. Michael Streeter