BROOKLYN - Fire crews were back at the scene Sunday of the Borough Park building explosion that killed at least one woman and injured twelve others.

Authorities say a woman who lived on the building's second floor remains missing, and could still be in the rubble. NYPD K-9 units are on scene assisting in search and rescue efforts.

As News 12 has reported, a possible gas explosion sparked a fire at the building located on 43rd Street at 13th Avenue just after 1 p.m. Saturday.

Ligia Puello, 64, was found dead in a stairwell.  Lourdes Rivera, a woman who claims to have known the victim, says everyone loved her and her death is a big loss.

Twelve others were injured, according to fire officials. One person suffered severe injuries, another person suffered "moderate" injuries, and 10 more suffered minor injuries.

The Department of Buildings has ordered evacuations at 18 surrounding units, including 12 residential and six commercial units. Officials say more than 50 people have been displaced due to the incident, and are being assisted by organizations that include the Red Cross.

Investigators believe the removal of a gas stove may have caused the blast. If so, it would mark the fourth gas explosion in the city in the past two years.

Gov. Andrew Cuomo has promised a state investigation into gas explosions in the city. Mayor Bill de Blasio is urging anyone who thinks they smell gas to call 911 immediately.