A sicko is fatally poisoning dogs, cats, birds and squirrels in Bay Ridge — sneaking around before dawn to carry out his cruel deeds, residents say.

“It’s animal genocide. We just want to find out who’s doing it,” distressed community leader Brian Baglioni, 24, told The Post.

The NYPD Animal Cruelty Investigation Squad is investigating the incidents in the Brooklyn neighborhood, police sources said.

Baglioni’s group recently began plastering fliers around the neighborhood bearing animal-corpse photos and the message, “Warning — animals are being poisoned in Bay Ridge. Cats, squirrels and birds are suffering extremely painful deaths. WE NEED YOUR HELP!!!”

Baglioni said nearly 100 birds, four stray cats, a dog and a few squirrels have been killed since the attacks began in August between 88th Street and 93rd Street from Fourth to Bay Ridge avenues.

A doomed dog, which belonged to an elderly woman, went into convulsions and died after eating something off the ground, residents said.

The disturbing acts prompted Baglioni to set up a camera on his 91st Street fire escape, which twice captured a suspected assailant in the act.

In a before-dawn video taken on Jan. 18, a man uses a pole to knock down a bird feeder from a tree. He then pours birdseed from the feeder onto the ground.

The man leaves and returns 20 minutes later with a container and dumps its contents — a bright-green liquid that cops believe is antifreeze — around the base of the tree and onto the birdseed, the video shows.

“It is utterly disturbing and ­malicious,” Baglioni said. “There is no reason to kill those animals. Whatever he’s doing is just wrong on so many fronts.”

Baglioni, a lifelong neighborhood resident, said someone has also been sprinkling boric acid and glass pieces in cat food that neighbors leave for outdoor ­felines.

Cops from the 68th Precinct are keeping an eye out for any suspicious activity, police sources said.