Seen in old nabe minutes before flight

IT’S THE FIRST CLUE in the mystery of the missing mayor.

Responding to an appeal from the Daily News about the whereabouts of Mayor de Blasio in Brooklyn before he used an NYPD helicopter to travel from Prospect Park to Queens, people are starting to provide details about how he filled the hours before his flight.

Clue one: Bar Toto — a favorite hangout.

Hizzoner, who continues to refuse to disclose what kept him so busy that he needed to take a taxpayer-funded whirlybird to Long Island City, was hanging out in business casual and strolling around his old Park Slope neighborhood on that Friday, Oct. 14, according to locals.

He had likely been at Bar Toto, the Italian eatery that often serves as his second office.

He’s there nearly every Friday — a day when his schedule usually gives him the afternoon off — making calls and catching up with former neighbors who stop by, according to sources familiar with his schedule.

The restaurant is just three blocks from Prospect Park, and a six-minute walk from where the helicopter took off during the evening rush hour.

“He’s comfortable there,” said one source.

Karrie Jacobs, a Brooklyn resident and design writer, said she saw the mayor around 3 p.m. in a white, button-down shirt with no jacket in the south end of the neighborhood walking in the direction of Bar Toto.

“I was walking up 14th St. and just as I got to Sixth Ave., I thought, ‘Boy, that guy looks familiar,’ ” said Jacobs.

Then she saw his NYPD security detail walking behind him and realized who it was. “He was talking very intently on his phone,” she said.

That 3 p.m. sighting helps fill in the gap from the mayor’s radio appearance at 1:25 p.m. and his chopper ride around 6:30 p.m.

Workers at Bar Toto con-