An investigation into the deadly explosion that blew the facade off of a Borough Park apartment building last Saturday continues, but Fire Marshals on Thursday ruled out the possibility that natural gas had caused it.

"The investigation into the cause preliminarily focused on the possibility of natural gas being involved due to information from the building landlord that the occupant of the second floor apartment—which is where the explosion/fire originated—had been removing a stove while in the course of vacating the apartment," said Fire Commissioner Daniel Nigro in a statement.

"Information obtained since then, and confirmed by examination of the building gas meters, found that there was no natural gas flowing to the second floor apartment since June 26... and that prior to the explosion no significant natural gas flow into any part of the building had occurred."

The NY Times points out that the fire was accompanied by thick black smoke, which is not typical of gas-leak explosions like the one that took place in the East Village this spring. Fire officials told the Times that black smoke is usually a signifier of burning gasoline or diesel fuel.

The Borough Park explosion occurred at 4206 13th Avenue near 42nd Street in Borough Park around 1 p.m. last Saturday, and more than 200 firefighters were called in to battle the blaze. The building contains a ground floor hardware and electronics store called Pots N Watts, and two stories of apartments.

Thirteen residents and pedestrians were injured in the blaze, and two were killed. 64-year-old Ligia Puello, a tenant on the third floor, was found dead in the building's stairwell. The city's medical examiner officially identified the second victim on Thursday, as 48-year-old Francisca Figueroa.

Figueroa lived in the same apartment where investigators initially believed a stove was disconnected from its gas hookup—possibly causing the explosion. She had recently been evicted from her home, and was in the process of moving out. She had also posted "suicidal thoughts" on social media, according to NBC.

NYPD detectives told the NY Times that Figueroa had also left some notes in the apartment. Written in Spanish, they "clearly indicate that she appears distraught and concerned,” a spokesman explained.

However, the NYPD stressed that until the cause of the fire is determined, it would be a stretch to speculate about motives. "I’m not going to comment on Ms. Figueroa’s state of mind," Chief of Detectives Robert Boyce told reporters.