NEW YORK (CBSNewYork) — Two people remain unaccounted for after an apparent gas explosion in the East Village that leveled three five-story buildings.

Flames and smoke were sent shooting into the sky after an initial explosion from the basement of 121 Second Avenue around 3:15 p.m. Thursday. The fire jumped to adjacent buildings, causing three to collapse. A fourth suffered extensive fire damage.

PHOTOS: Second Avenue Building Explosion

Authorities said they are searching for 23-year-old Nicholas Figueroa, who was on a date at the Sushi Park restaurant right before the building fell, and a restaurant worker, Moises Locon.

“We have two people that we know for sure are unaccounted for,” Mayor Bill de Blasio said at a news conference Friday afternoon. “Two people based on eyewitness accounts.”

It’s was a sleepless night for the Locon family as they waited for Moises Locon to return to his Long Island City home, to no avail.

(Credit: NYPD)

(Credit: NYPD)

“He’s my family, he’s my brother and I just want to find him and that’s it,” his older brother Alfredo Locon told CBS2’s Diane Macedo.

Locon was working as a busboy at Sushi Park when the explosion destroyed the entire building.

Alfredo Locon said they first learned about the blast from a waitress at the restaurant around 9 p.m.

“She says my brother was in the in the restaurant,” he said.

The family then went to the blast site and nearby hospitals but none had any record of him.

Macedo asked his younger brother in Spanish how he felt about his brother being unaccounted for. He said he feels devastated at his brothers disappearance but still can’t imagine that he might be not be alive.

Nicholas Figueroa’s family said he and his date were paying for their meal at the time of the blast.

(Credit: NYPD)

(Credit: NYPD)

“Nobody knows what’s happening,” his brother Brandon Figueroa told CBS2’s Ilana Gold. “It has me shaking. It’s very nerve-racking just to think about it.”

“I’m just really worried he’s going to remain missing and no one’s going to truly find where he is,” Brandon Figueroa told CBS2.

His date’s family says she was being treated for her injuries at Bellevue Hospital.

Nicholas Figueroa’s cousin, Anthony Figueroa, said the family is praying for his safe return.

“I just hope he’s OK and I’m praying for the best,” he told 1010 WINS’ Kevin Rincon. “I know he’s strong and I know he’ll overcome anything.”

Investigators did a thorough search of the building, but sources told CBS2 they found no signs of him. His siblings keep calling his cell phone, but it goes straight to voice mail.

“My brother is a strong guy,” his brother Neal Figueroa told WCBS 880’s Peter Haskell. “I just want my brother to be safe, I want him to smile again. I want him to be home.”

“I’m just really worried he’s going to remain missing and no one is going to truly find where he is,” Brandon Figueroa said. “I want to have that confidence, but there are so many factors that go against it.”

Earlier, authorities said they were trying to determine if six others who were reported missing were connected to the blast. Chief of Detectives Robert Boyce said Friday that list has now been narrowed down to one.

It’s still early in the investigation, but city officials believe it was a gas-related explosion.

Con Edison inspectors were at 121 Second Avenue before the blast looking at the installation of a new gas meter and pipes, work the utility said was being done by a private contractor.

But Con Ed said it failed the inspection partly because the space for a new meter wasn’t big enough.