LOWER EAST SIDE, Manhattan (PIX11) — An alleged arsonist has been federally charged with setting a Lower East Side spa ablaze with a worker inside, prosecutors announced Friday.

Mario Lucas, 46, faces a single count of arson for the June incident, in which he too was trapped inside the burning building before a good Samaritan came to the rescue, authorities said.

“Intentionally setting a fire is a heinous crime, and doing so while knowing there is a person trapped inside is reprehensible,” said acting FDNY Commissioner Laura Kavanagh in a statement. “We are grateful to our Fire Marshals and all law enforcement for quickly apprehending this man and keeping him off our city’s streets.” 

Lucas, of Guatemala, walked into the spa on Eldridge Street near Broome Street around 4:45 p.m. June 19, and appeared to strike up a conversation with a woman working inside, officials said. 

When the worker left the lobby to head into a back room, Lucas allegedly opened his backpack, pulled out a white plastic bag appearing to hold a container of liquid, and poured the liquid around the lobby, prosecutors said. He then allegedly used a lighter to set the liquid on fire, quickly engulfing the lobby, according to authorities. The NYPD previously identified the liquid as gasoline.

Lucas then tried to leave the spa through the front door, but it wouldn’t budge, officials said. Meanwhile, a crowd gathered outside the burning spa, and a man used a bar stool to force open the door, prosecutors said. 

Lucas ran out of the spa, followed closely by the worker, officials said. Lucas allegedly kept running down Eldridge Street, shedding his hoodie, shirt, and backpack along the way, appearing to have sustained severe burns, investigators said, citing surveillance footage.

Cops intercepted Lucas about two blocks from the spa and put him in an ambulance, authorities said. Both Lucas and the 60-year-old worker were hospitalized, suffering from burns but expected at the time to survive.

Investigators eventually tied Lucas to the arson, formally arresting him in August but not announcing the charges until Friday. Prosecutors did not specify an alleged motive behind the arson.

“As alleged, the arson Mario Lucas sparked in June was not just a crime against a single victim in one business, but a violent assault that endangered an entire community and all the first responders who rushed in to help,” said NYPD Commissioner Keechant Sewell in a statement.

If convicted, Lucas faces a mandatory minimum sentence of seven years in prison, and a maximum of 40 years.