Cops busted the suspected triggerman accused of fatally shooting a 21-year-old man in a Brooklyn housing complex Monday night, cops said Tuesday.

Tejion Lee, 25, of the Bronx, was slapped with murder and a weapon possession charge in the death of 21-year old Shamar Davis, authorities said.

Davis was found dead in the 13th-floor hallway of his apartment building in Brownsville’s Tilden Houses with multiple gunshot wounds late Monday.

A dispute between neighboring apartments on the floor is believed to have set off the deadly encounter, according to sources.

The murder weapon was later found by cops after being tossed from an apartment window.

Lee was awaiting arraignment Tuesday night.