Inside the mystery which has stunned Australia: Why were this beloved schoolteacher and her cherished baby girl stabbed to death - and why did their brilliant scientist father flee the house of

Mother and baby daughter found dead in suspicious circumstances south of Brisbane

A mother and her baby daughter have been found dead at their family home south of Brisbane under suspicious circumstances.

Kate Paterson, 38, and April, 1, were found dead after the child’s father, 39-year-old Blake Seers, was struck by a vehicle just a few hundred metres from their Logan home.

Witnesses said he was covered in blood when he ran into oncoming traffic outside a supermarket on Beaudesert Beenleigh Road in Bannockburn, 35 kilometres south of Brisbane, about 7.30am today.

Kate Paterson, 38, and April, 1, were found dead after the father of the child, 39-year-old Blake Seers, was struck by a vehicle just a few hundred metres from their Logan home. (9News)

“A person saw him running along the street and seemed to have something, some sort of an injury to the neck,” Detective Superintendent Chris Ahearn said.

Shortly after, officers went to his nearby address to notify his family but instead found Paterson and April dead with stab wounds.

“What I indicate is, on cursory look, it looks like the injuries are consistent with an edged weapon,” Ahearn said.

Neighbour Joseph Patraucean said his mother heard cries from the home early this morning.

“She heard like a young baby screaming, like a very young one,” he said.

Detectives and forensic investigators spent much of the day coming in and out of the house to try to piece together exactly what unfolded.

Police were also seen retracing the man’s steps, marking out a trail of blood.

Queensland Police detective superintendent Chris Ahern.Queensland Police detective superintendent Chris Ahern. (9News)

“Our investigations are focusing heavily on the nature of their relationship and those living arrangements at that house,” Ahearn said.

“Our minds are open as to what’s gone on here.”

Seers was tonight in a serious condition under police guard at the Princess Alexandra Hospital.

“Clearly we’re anxious to speak with him so that we can get a fuller appraisal of the circumstances,” Ahearn said.

Ahearn encouraged members of the public with dashcam or phone vision in the vicinity of the home or outside of the supermarket between 7am and 8.30am today to contact police.

“We’d like to hear from them, they may be able to assist us with our investigation,” he said.