3 slain in LI break-in

Three people were fatally shot Friday in a home invasion on Long Island — with a baby later found unharmed inside, cops said.

A police source told The Post the triple-slaying may have been drug-related.

The bloodshed occurred midday at a house on Overlook Drive in Farmingville in Suffolk County, police said.

Cops arrived to find a man and two women with fatal gunshot wounds, according to Suffolk County Detective Lt. Kevin Beyrer.

At least one gunman kicked down the front door, breaking the doorjamb, and opened fire, according to police.