ST. LOUIS (AP) — A St. Louis County man is dead after allegedly barging into a home and threatening his ex-girlfriend and another man in a shooting that could fall under a Missouri law that gives people leeway in use of deadly force inside their homes.

St. Louis County police told the St. Louis Post-Dispatch that 41-year-old Joel Wright was shot once in the head about 10 p.m. Tuesday in the town of Winchester.

The 31-year-old man who shot him was arrested on suspicion of second-degree murder. He was released when prosecutors declined to immediately charge him in a case that may fall under Missouri’s “castle doctrine” law.

Police spokesman Shawn McGuire says Wright had made threats against the couple earlier in the evening.