5 Indicted in Deadly NYC Building Fire Caused by Alleged Illegal Gas Line

— -- Five people have been indicted today in connection with a fatal March 2015 building explosion in Manhattan's East Village that left two people dead and more than 20 injured.

Maria Hrynenko, 56, the building's owner; her son Michael Hrynenko, 30; Athanasios Ioannidis, 59; and Dilber Kukic, 40, were charged with involuntary manslaughter in addition to other charges. Andrew Trombettas, 57, faces lesser charges. All of the defendants pleaded not guilty today.

Investigators say the explosion was caused by an illegally tapped gas line.

"When you are responsible for the construction, renovation and the powering of buildings, you are responsible for handling dangerous instruments and when you tinker around with a gas system, the electrical hookups, as happened here, you have, in effect, weaponized the building," said Manhattan District Attorney Cyrus R. Vance Jr. during a news conference today.

Around 3:17 p.m. local time, March 26, witnesses reported what sounded like an explosion at Sushi Park restaurant at 121 Second Avenue, which is at the bottom of a five-story pre-war building that houses a handful of residential units.

Court documents said that Maria Hrynenko had hired Kukic, a general contractor, to work on some of her properties including the building at 121 Second Ave. Ioannidis had been hired by Kukic to handle plumbing work. Ioannidis allegedly used Trombettas' master plumbing license and credentials, which is illegal.

Michael Hrynenko, according to court documents, was managing the building at the time.

Roger Blank, the attorney for Ioannidis, said that his client extended his deepest sympathies to those affected by the explosion.

"It's a tragedy," he told ABC News today. "It's a horrible tragedy."

Blank said that his client was going to vigorously contest the charges against him.

Two people were killed -- Moises Ismael Locon Yac and Nicholas Figueroa -- and 22 others were injured. Two of the most seriously injured victims were Michael Hrynenko, a building co-owner, and Kukic, who helped carry Hrynenko away from the blast, police said at the time.

"The seven-alarm fire that killed two people and engulfed three buildings in March 2015 was caused by a foreseeable, preventable, and completely avoidable gas explosion," Vance said.

Vance said the defendants rigged a series of "illegal and highly dangerous" pipes and valves to get gas into the apartments that rented for $6,000 per month.

Mark Bederow, an attorney representing Kukic, told ABC News that his client had not admitted any involvement in the explosion.

"This is a tragic and sad case but we need to go on facts and evidence, not emotion, which is what we intend to do," Bederow said.

Lawyers for the other defendants were not immediately available for comment.

Inspectors from Con Ed, the local power and gas company, arrived at the building March 26 to meet with the contractor to evaluate work being done by a plumber in the basement of one of the buildings, according to police. The work failed inspection.

Vance said that later that day, a worker at the sushi restaurant on the ground floor smelled gas and alerted Maria Hrynenko. She then sent Kukic and her son into the building. They smelled gas and sprinted out without notifying anyone moments before the explosion.

In a statement, Mayor Bill de Blasio said that those charged "showed a blatant and callous disregard for human life."

"We have cooperated with the authorities throughout this probe and provided all documentation and information they requested. We continue to work closely with the city to immediately report unauthorized conditions when we find them, as well as take actions to eliminate any hazardous condition," Con Ed said in a statement.

Vance said the case is a deadly reminder to building owners to resist shortcuts at a time when development in this and many other cities is at a breakneck pace.