HALTOM CITY (CBSDFW.COM)A North Texas fire department has identified the adult and three children killed in a Thursday afternoon house fire.

According to Haltom City Fire/Rescue, 52-year-old Maritza Garces is confirmed dead. She was the only adult in the house, in the 4900 block of Colonial Park, when the blaze started.

Firefighters also pulled three children from the house. They have now been identified as Gene Perrera, a 5-year-old boy, Jayleen Rayos, a 3-year-old girl and two-month-old baby boy Jaime Moran Jr.

When asked, Haltom City fire official Perry Bynum said investigators don’t know exactly why the four weren’t able to get out of the house. “Smoke inhalation is usually the cause of most individuals who are caught inside of a home. The cause of them not being able to get out of the home… I’m not for sure. I wouldn’t even speculate.”

While paramedics administered medical care at the scene, all four victims were pronounced dead at the hospital.

In addition to Haltom City Fire/Rescue, fire crews from North Richland Hills and Fort Worth helped extinguish the blaze that began around 5 p.m. Thursday. Emergency crews were sent to the house after a neighbor called 911 and reported seeing smoke coming from the house.

Haltom City fire investigators have officially determined the fire started in the front of the house. “There was a live Christmas tree in the living room and the area of origin was near that Christmas tree,” Bynum explained, adding, “But we have not determined what caused the fire.”

CBS 11 News reported Thursday night that Christmas decorations were still up outside and inside the house.

Arson investigators are still looking into the incident, trying to determine exactly what sparked the fire.