The deadly 2015 East Village gas explosion landed three people in prison for manslaughter, the Manhattan District Attorney announced Friday.

Landlord Maria Hrynenko, 59, unlicensed plumber Anthanasios 'Jerry' Ioannidis, 63, and contractor Dilber Kukic, 44—who were all involved with setting up a shoddy gas system that sparked the blast—were sentenced to four to 12 years in prison on Friday.

"If you cut corners based on expediency and profit and kill or injure New Yorkers in the process, you are engaging in criminal conduct and my Office will seek significant prison time," District Attorney Cy Vance said in a statement.

The explosion at 121 Second Avenue resulted from an illegal gas delivery system installed in the back of the building's basement, prosecutors found. The landlord Hrynenko had hired general contractor Kukic to renovate the property, which had four floors of apartments and a sushi restaurant on the ground floor. Kukic then hired Ioannidis, an unlicensed plumber, to do the work. Ioannidis paid another plumber to allow him to use his credentials to get required permits from the city and Con Edison. (That plumber, Andrew Trombettas, pleaded guilty to lesser charges and got probation and community service in March.)

The same day as the explosion, March 26th, 2015, Ioannidis and Kukic manipulated the gas lines during a Con Edison inspection by shutting off the gas supply and opening the shut-off valves. They failed the inspection—though Con Edison officials were still not aware of the illegal system that was behind locked doors. The gas supply was turned back on after Con Edison left without shutting the gas valves, and gas flowed through pipes into the sushi restaurant.

About an hour later, the building exploded, seriously injuring 13 and killing two: 26-year-old Moises Locon, who worked at the ground floor restaurant, and 23-year-old Nicholas Figueroa, who was on a date. It also leveled three buildings.

Hrynenko's son and building manager, Michael Hrynenko, Jr., was indicted, but died at 31-years-old awaiting trial. Hrynenko, Ioannidis and Kukic were convicted for various counts of manslaughter, assault, reckless endangerment in November. Ioannidis was also convicted for falsifying business records.

Vance said developers and property owners should "keep today's sentencing in mind as New York's building boom continues into 2020."