"There is a possibility here that the gas line was inappropriately accessed internally" by people in one of the destroyed buildings, but officials need to get access to its basement to explore it further, de Blasio said.
The number of people injured in Thursday's blast rose from 19 to 22, with four critically injured. Police were searching for at least two people: Nicholas Figueroa, a bowling alley worker who had been on a date at a sushi restaurant in the building where the destruction was centred, and Moises Lucon, a worker there. Authorities also were exploring whether a third person was unaccounted for, Chief of Detectives Robert Boyce said.
Preliminary evidence suggests an explosion amid plumbing and gas work inside the building was to blame.
Inspectors with utility Consolidated Edison had been to the East Village building to check on ongoing work to upgrade gas service. The utility said the work didn't pass inspection, so the new gas line was locked to ensure it wouldn't be used, and inspectors gave instructions and left. Con Ed said inspectors didn't smell gas.
But 15 minutes later, the sushi restaurant owner smelled gas and called the landlord, who called a general contractor, Boyce said. No one called 911 or Con Ed, however, de Blasio said.
The contractor, Dilber Kukic, and the owner's son went into the basement and opened a door, and then the explosion happened, burning their faces, Boyce said.
The building had an existing gas line intended to serve the sushi restaurant; the work underway was to put in a bigger line to serve the entire building, Con Ed President Craig Ivey said. As for whether the largely vacant apartments were getting gas from the existing line, "That's a great question," he said.
De Blasio wouldn't say more about why officials believe the existing gas line might have been tapped. But the building had a history: Con Ed found an unauthorized gas pipe there in August after getting a report of a gas smell, according to a city official briefed on the information. The official wasn't authorized to discuss the ongoing investigation publicly and spoke on the condition of anonymity.
The pipe was gone when Con Ed checked again 10 days later, the official said. Some of the people involved with the building are not co-operating with investigators, the official said.
The building's managing agent didn't immediately respond to messages seeking comment Friday.
Firefighters used high-powered water towers to douse the wreckage, a giant wave of crumbled brick, twisted metal, splintered wood and bits of residents' belongings. Rubble was still strewn across parked cars, and a menu from the sushi restaurant and other debris were scattered across the surrounding streets.
Figueroa graduated from Buffalo State College in December. He has been working at Bowlmor Chelsea Piers as a front desk attendant and laser tag attendant.
On Thursday night, Tyler Figueroa said his brother and his date were paying for their meal when the blast occurred. The date, who is in the hospital, remembers only stumbling outside before losing consciousness, Tyler Figueroa said.
"I just pray my brother shows up," he said.
Efforts to reach Lucon's family were unsuccessful.
The blast echoed through the city's arts community, destroying "Sopranos" actress Drea de Matteo's apartment — she posted photos on Instagram of "a hole where my NYC home of the last 22 years once stood" — and spurring the cancellation of five performances of the propulsive show "Stomp," which is at a theatre near the site.
Kukic, who's facing an unrelated bribery charge, declined through his lawyer to comment on the circumstances surrounding the explosion. City records show Kukic got a permit last June for plumbing, flooring, removing partition walls and other work at the building.
Kukic was treated and released from a hospital, and "his thoughts are with the people who are injured," said his lawyer, Mark Bederow.
Kukic is a relatively minor player in a 50-person bribery case authorities unveiled last month. He's accused of paying $600 to an undercover investigator posing as a housing inspector to get violations dismissed at two upper Manhattan properties. He has pleaded not guilty.
Associated Press writers Colleen Long, Mike Balsamo, Kiley Armstrong and Mark Kennedy in New York and Frank Eltman in Mineola contributed to this report.