Baretta feels remorse for shooting a small time drug dealer dead.
His younger brother Niki Coppelli vows revenge. He ends up wounding Billy accidentally while trying to get Baretta.
Sal Bodine the drug dealer who employs all the pushers decides he can use Bily to get back at Baretta.
Baretta wants to get through to Niki and not to end up like his brother.
It seemed to be a common feature in these old cop shows where the tough no nonsense cop suddenly acts like this is the first time he has killed someone. I remember Miami Vice did something similar several years after it had been going and blown away dozens of baddies.
Given Baretta was being shot at by the young hoodlum and three others joined him in shooting at Baretta. I think Baretta's action was reasonable.
I am not sure what protocol was like in those days. After shooting the hoodlum, did Baretta need to be waiting outside the hospital ward.
What was that about giving his personal information to Niki. Did Baretta not realize that Niki and his friends might want revenge.