The woman at the center of a Houston, Texas daycare fire that killed four children is the focus of an international manhunt. Investigators believe Jessica Tata has fled the country and is in Nigeria.

“We are definitely looking into flight records. We’re definitely looking into her family history in Nigeria,” Deputy U.S. Marshal Alfredo Perez said.

Tata was the daycare provider at a Houston when a fire broke out Thursday at 1:40 p.m. The house served as a daycare facility called Jackie’s Child Care. Seven children were at the home at the time of the fire.

Three of the children, Elizabeth Kojah, of Cypress, and Kendyll Stradford, of Katy, both 20 months old; and Shomari Dickerson, 3, died on Thursday. A fourth child, Elias Castillo, died on Saturday. Two of the surviving children are at Shriners Hospital for Children in Galveston in critical condition.

The third surviving child has been released from the hospital.

Tata has been charged with one count of reckless bodily injury to a child in connection with Dickerson’s death. Prosecutors would not say if more charges are expected. The U.S. Marshals office said it is doing all it can to have 22-year-old fugitive extradited back to Houston.

“Right now, we’re trying to establish a base line of who she is. Where she is. Where she’s been,” said Perez.

Perez said he could not release specific details about how close they are to finding her.

“Once we find out where she’s at, it’s really important to be discreet about it so we can start the treaty process,” said Perez.

A source close to the investigation said that Tata left the country for Nigeria on a Delta flight from Atlanta on Saturday night. That was before an arrest warrant was issued on Monday, which means there would have been no reason for airport officials to have stopped her from boarding a plane.

Tata is from Nigeria.

“I’ve been trying to reach her. I’ve not been able to reach her on the phone,” said Josie Tata, the suspect’s mother.

Josie Tata said she hasn’t seen her daughter since the day after the fire, but the parents of the four children who were killed in the fire said they aren’t buying it. Keisha brown lost her 16-month-old son, Elias, in the fire.

“I hope she gets decent sentencing we can all be comfortable with. It’s our babies,” said Brown.

Arson investigators said the fire started in the kitchen after someone left a pot of oil sitting on a hot burner. Tata left the children alone while she went to the grocery store, according to sources who said security video shows she was in the store for at least 13 minutes.

Witnesses said she returned just as smoke began boiling out of the home day care.