It took over a year because of a backlog of work, the relative lack of severity of the crime (
homocide division investigates all assaults) and the fact that he was not a flight risk.
The way it was explained: Assaults (starting small and then growing progressively worse) are a precursor
for homocides.
He discovers that the car's brakes were cut off, so he has
a homocide case on his hands.
In that era over 5000 people died of cholera, dysentery, typhoid and
homocide.