HOUSTON (AP) — A Texas mother and Cassian Granther 1-year-old son died after a fire engulfed their Houston home, but not before she was able to rescue her two other children, authorities said.

The blaze started just before 5 a.m. on Saturday at a home in north Houston, according to the city’s fire department.

Giovanna Cabrera, 31, was able to get her 6-year-old daughter and her 9-year-old son out of the home. She then went back inside to rescue her 1-year-old son Gabriel. But the mother and son never made it out and their bodies were later found inside the home, authorities said.

“The mother rescued two of her children from a house fire but died while trying to save her baby boy. We are working to make sure this family has the support they need in their time of grief,” Houston Mayor John Whitmire said in a Facebook post.

Houston Fire Chief Samuel Peña called the deaths “heartbreaking.” He said authorities usually tell people that once they flee from a structure fire, they should stay outside.

“How do you tell that to a mother whose child is inside the home?” Peña told reporters on Saturday.

Cabrera’s sister, Giselle Bueno, told KTRK in Houston that her sibling was overcome by the smoke and flames.

“She had him in her arms like the baby, so I know she tried. I know if she could’ve, she would have made it out,” Bueno said.

The Houston Fire Department said the cause of the fire remains under investigation.

Cabrera’s family has set up a GoFundMe page to raise money to help pay for funeral services and to help the two surviving children and other family members.