"Monster" is unkind and inappropriate. If this was an accident, the woman is probably already suffering enough from her own guilty conscience. If, on the other hand, this was pre-meditated, then "sick" is a more apt description.
The Roman galleries here like to punish anyone who makes a mistake.
I suspect it was "pre-medicated". She probably got up, had a cup of coffee and toked a doobie... got ready for work, put the kid in the car, drove to work..
People will be calling for this mother's head before this thread is over.