Warning - this story may be distressing to some readers
Police believe the deaths of Henry Shepherdson, 38, and his nine-month-old daughter Kobi on Wednesday were a murder-suicide, with witnesses reporting they saw the man jump from the tourist attraction in Williamstown.
Onlookers tried to help baby Kobi following the fall but paramedics who arrived about 4.30pm found her unresponsive and were unable to revive her.
Kobi Shepherdson died in a suspected murder-suicide.(Nine)
The man was found dead.
A police statement said early investigations showed a history of domestic violence between Mr Shepherdson and the mother of Kobi.
A case against Shepherdson for alleged assault, and for allegedly threatening his partner and baby last year was dropped.