The following event occurred before WT was born when his sister was in her 1st year. I know that in the past I have read that police contacted FACS after this event as they were so concerned at the bio mother's behaviour. If anyone else can find that missing link I'd be grateful. Seems to be in articles published from January to May 2017
Missing toddler: William Tyrrell's mother has violent past
In 2010, Tyrrell had gone to the Ryde area to celebrate her 22nd birthday with family members at her father's house. One relative was at the time subject to a court-ordered curfew.
Police were called to the house after neighbours reported noise in the street and they found Tyrrell in the road.
During a heated exchanged which ensued with a female police officer, she punched the officer in the face.
Tyrrell was convicted and sentenced in Ryde Local Court in August 2010 on charges of assaulting an officer and resisting an officer in the execution of duty, fined a total of A$500 (NZ$535)and placed on a 12-month bond.