CCTV footage will be used to help determine how a 10-week-old baby girl was left fighting for her life after suffering "serious injuries" in an incident earlier this week.
One theory being examined is the young girl fell out of a pram. However, gardaí are investigating all lines of enquiry.
The Irish Independent has learned that the infant was brought to Our Lady of Lourdes Hospital, Drogheda, Co Louth, on Monday.
She was later transferred to Temple Street Hospital in Dublin where she remains in a critical condition.
"The baby is in a critical condition; she suffered very serious injuries," a senior source said last night. "A large number of her distraught family members are at the hospital with the child."
The baby is the child of young Irish parents and had been living in an apartment in Ardee, Co Louth.
Sources have revealed that gardaí have received an account of what happened to the child.
One line of enquiry that officers are probing is a claim the baby suffered the horrific injuries after she was thrown out of her pram when "unknown men" approached and "accidentally" pushed into the male who was wheeling the baby in a public area in Ardee.
Gardaí are investigating a report that three males knocked over the man and the baby he was pushing in a pram at the time.
Last night, sources said these reports were just one strand of the massive Garda investigation and "everything was being looked at" in the tragic case.
The alleged incident happened at 7pm on Monday at a location close to the banks of the River Dee.
Yesterday, officers conducted a number of searches in the Ardee area and gathered CCTV. No arrests have been made in the investigation.
A Garda spokesman said: "A 10-week-old girl was removed from a local hospital in Co Louth on Monday and transferred to a Dublin hospital where she remains in a serious condition."