The pair lived in the flat with their two dogs. It is believed that Giselle has just one family member, her sister, living locally.
Sinn Fein Councillor Charlie Casey said he was briefed by a police officer, who said that the full extent of what has happened will frighten the wider public.
He told Belfast Live: “What he did say was we can rule out gas and carbon monoxide.
“Other than that it’s a bit of a disaster. When the news and the information does come out it will be a shock to the entire community.”
Bodies of mum, daughter and man lay undiscovered for three days in Co Down