Gardai have not been able to interview the Dublin-based nurse whose three children were found dead at their home in Newcastle, Co Dublin, on Friday night.
Deirdre Morley, aged in her 40s, remained last night in Tallaght Hospital, where she was being treated after a suspected overdose four days ago.
She is expected to recover, after being found wandering in a disoriented state near a graveyard on Friday evening shortly before the bodies of Conchur (9), Darragh (7) and Carla (3) were discovered.
"She has still not been deemed medically fit to be interviewed, but is expected to survive," a senior source told the Herald last night.
"Gardai are conducting a massive investigation to collect evidence and gather a large number of witness statements, all of which can then be put to this woman when she is deemed medically fit to be questioned."
Members of the community have rallied around to show their support, particularly to the children's heartbroken father Andrew McGinley.
Gardai believe "some form of sedation" was involved in the deaths of the three children, but it has not yet been established what drug or drugs were used.
This will be determined by the results of toxicology reports, which are not expected to be available until later in the week.
It is not believed any drugs were administered by injection as no visible marks were found on the children's bodies.
However, it is suspected that some or all of them may have been smothered after being sedated.
Gardai are not looking for anyone else in relation to the tragedy, and have recovered two notes from the house, including one that read: "Call 999, don't go upstairs."
The local Gaelscoil of Scoil Chronain in Rathcoole has said it is "deeply saddened by the sudden deaths of pupils Conchur (9) and Darragh (7) Mac Fhionnghaile and their sister Carla (3)".
"It is a tragedy for our community," a spokesperson said.
"Our sympathy, thoughts and prayers are with the McGinley and Morley families and all their friends."
Speaking about the two boys, the spokesperson added that Conchur was a pupil in Room Three while Darragh attended Room One.
"They were both wonderful boys and it was a pleasure to have them in our school. They will be greatly missed by all who knew them.
"Offers of support have been pouring in and are really appreciated.
"Our school has implemented our critical incident management plan.
"Psychologists from the National Educational Psychological Services (NEPS) have been with us over the weekend and will continue to support and advise us in the coming days."
NEPS psychologists work with primary and post-primary schools to offer support in the areas of learning, behavioural, social and emotional development.
The spokesperson added that the school will remain open and asked that people respect the need for privacy.
Youngest child Carla attended the Happy Feet nursery in Rathcoole, and staff members from there and from the primary school attended a tribute mass over the weekend.
Meanwhile, South Dublin County Council opened a book of condolences in the wake of the tragedy at the Town Hall in Belgard Square North in Tallaght.