Brooklyn residents said Sunday that they fear the return of the bad old days of “Crooklyn” — and placed the blame squarely on Mayor Bill de Blasio — after a bloody weekend in which at least 19 people were shot in the borough.

The carnage included nine revelers struck by bullets at a house party, a teenager shot during a drive-by, and a man fatally gunned down in a housing-project courtyard — all in an hour-and-a-half period early Sunday.

That followed eight people being shot in six hours Friday into Saturday.

“I locked the door and ran into the back when I heard shots,” said Mahdi Alabdi, 52, who works overnight in a deli across the street from the bullet-riddled East New York house party. “I never did this before. I do it a few times now.”

Nursing aide Anne Gordon, 25, who also lives near the scene, seconded the sentiment.

“This was never the best area, but it has gotten worse out here since this new mayor,” she said. “He seems out of touch.’’

Lifelong borough resident Richard LaTorre, 55, fumed that former Park Sloper de Blasio “left Crooklyn for Manhattan with his entourage of bodyguards and SUVs.”

“He has his protection from all this. What about the rest of us?” LaTorre said.

In Prospect-Lefferts Gardens, where a 15-year-old boy was shot in the stomach during a multi-car drive-by attack, a neighbor who was nearly caught in the hail of bullets said the area is on the decline after years of improvement.

“This is supposed to be a nice, safe neighborhood now,” said Patrick Desravines, whose apartment overlooks several storefronts and cars that got hit.

A 42-year-old woman who lives in Kensington tied the worsening situation to de Blasio’s curbs on the NYPD’s stop-and-frisk practice.

“I have teenagers, and it scares the crap of me,” said the woman, who gave only her first name, Ellen. “You have to watch yourself more than you used to.”

Cops guarding de Blasio wouldn’t let reporters get near him at a parade in Queens, but a spokeswoman said Hizzoner “takes very seriously each incident and has directed NYPD to beef up its presence in these areas.

“Overall crime is going down, but Mayor de Blasio will continue to be diligent about preventing crime and locking up criminals,” press secretary Karen Hinton added.

Additional reporting by Dana Sauchelli, Tom Wilson and Amber Sutherland