Hi, new here!
For what's worth, I always think of that saying "when you hear hoof beats think horses not zebras". While there are some peculiar aspects of the crime, the most likely scenario is that the child was killed by her parent or primary caregiver. Statistically speaking, this is most likely, as children are more likely to be harmed by a person known to them than a stranger. This is also the most obvious explanation of why the child was never reported missing.
Apparently, there are five types of filicide:
1. Altruistic motives the parent truly believes that the child is better off in heaven, or they believe that the childs suffering would be unbearable if they have to live.
2. Parent is psychotic/has psychotic break.
3. The fatal battering this is where the parent uses physical abuse to punish what they perceive as bad behaviour and the child dies during a beating or through violent action such as being thrown into a wall.
4. Covering up an unwanted birth (this would generally happen only to newborns, the case of Tegan Lane is an example)
5. Revenge against the ex such as the murders of Luke Batty and Darcy Freeman. These murders are usually carried out publicly with no effort made to conceal the crime (quite the opposite actually because the point is to maximise the exs pain)
This murder probably fits with types 2 and 3, which are physically violent crimes, occurring in an act of rage. Type 1 is usually a death that wouldnt leave serious physical injury to the skeleton such as crushing up sleeping pills in the childs milk or driving them into a lake to drown, Type 4 is a crime usually committed right after birth (although rare cases have been found in older children where the mother wanted a new life no strings attached). Type 5 is not concealed by the perpetrator and certainly never unreported to the police by the other parent.
Keisha Abrahams died of a "fatal battering" and there were as many as five or six visible injuries to her jaw -- these injuries were able to be seen on her skeleton over a year after her death and were judged to have occurred immediately prior to death. Perhaps something similar happened to this child.
My feeling (and I could be completely wrong) is that this is an unsophisticated crime. The person who did this is not cunning or a criminal mastermind. They just haven't been caught yet because no one has realised that their child is missing. Leaving the suitcase by the road? Maybe they did want it to be found, maybe they were trying to confuse the police, or maybe they just needed to get rid of it in a hurry and leaving it anywhere was fine as long as it wasn't found in their immediate possession.
