Updated

A 19-year-old awaiting trial on murder and other charges in the shooting death of a Las Vegas mother of four is being hit with a separate felony charge alleging that he held a knife to the throat of a 13-year-old boy.

Prosecutors on Monday filed a battery with a weapon charge alleging that Erich Milton Nowsch Jr. used a black-handled folding knife to threaten the boy during a Feb. 15 street confrontation witnessed by the boy's sister and two other girls.

A police report alleges the threat happened three days after 44-year-old Tammy Meyers was mortally wounded in what authorities first called a road-rage case.

Prosecutors now say Meyers' death may have resulted from a tragic chain of coincidences, including fears by Nowsch that someone was following him.