Post mortem examinations on the bodies of John Butler and his two daughters have been carried out at Cork University Hospital.
Six-year-old Zoe and two-year-old Ella died at their Ballycotton home in Co Cork yesterday before their father, John, who had been treated for depression, died when his car crashed and burst into flames.
Preliminary results indicate that both children died of suffocation. It had initially been thought that they died of strangulation.
Preliminary results from the post mortem examination conducted on the body of their father indicate that he died from burn injuries and from smoke inhalation after his car crashed on the approach road into Ballycotton.
Investigators are attempting to piece together the events in the days and hours leading up to the deaths and have appealed for the public's assistance.
The children's mother, Úna Butler, is being comforted by family in east Cork.
Support services have been put in place in the community in Ballycotton.
At Realt na Mara National School, where Zoe was a pupil, two psychologists from the National Educational Psychological Service are supporting parents and the staff to help the 97 pupils in the days ahead.
Investigating gardaí have sought the public's help in accounting for the whereabouts of a red Toyota Yaris, registration 02 C 1526, yesterday morning.
They are particularly interested in its whereabouts between 9am, when its male occupant bought petrol in Shanagarry, and 9.40am, when it was involved in a fatal crash at Ballycotton.
Anyone who may have seen this vehicle between these times or have any information is asked to contact Midleton Garda Station on 021-4621550.
