Brendon Toohey, 38, faced a two-week trial in the Supreme Court at Bathurst Court House before the 12-person jury handed down its verdict.

Toohey was found not guilty of murdering the 11-month-old baby before the jury delivered its guilty verdict for manslaughter.

Toohey had always maintained the baby suffered critical injuries when she fell from a trampoline and hit her head on the lid of a concrete septic tank as he was taking clothes off the washing line at a Mandurama home, about 30 kilometres south-west of Blayney.

At 11am on April 2, 2014, Toohey arrived at the emergency department at Blayney Hospital and raised the alarm.

Nursing staff, who saw the child was clearly seriously ill, assisted the accused and took the baby into a treatment room where, along with other medical staff, they performed extensive treatment including breathing assistance, CPR and the administration of medication.

The treatment continued long enough for the child's mother to be brought to the hospital but the baby was declared deceased at 12.40pm.

Detectives from the State Crime Command’s Homicide Squad and Chifley local area command officers formed Strike Force Zarebski to investigate the incident.

At the time of the incident, Chifley Local Area Command Detective Inspector Luke Rankin said police were focusing their investigation on the family’s movements in the 24 to 48 hours leading up to the “sudden and unexplained” death. 

Police arrested Toohey about a week later and he was charged with murder.

He will be sentenced for manslaughter in September.