A man wielding two swords and wearing a fencing mask was fatally shot by cops inside his Long Island home Tuesday night, authorities said. 

Alan Weber, 54, was “acting violent” inside the single-family house on tree-lined Mander Lane in Elwood when a neighbor called 911 around 8:45 p.m., according to Suffolk County Police. 

When officers arrived, Weber was screaming and breaking items in the home — and refused to step outside, cops said.

Cops then stepped into the home, where Weber confronted them while wearing a fencing mask and brandishing two fencing swords, according to Patch. 

Cops initially tased Weber, but the stun gun did not deter the sword-wielding man.

Then one cop opened fire, striking Weber, police said. 

Weber was taken to Huntington Hospital, where he was pronounced dead. 

The investigation was ongoing Wednesday afternoon, authorities said.