A probable cause hearing has been postponed for the mother of three children who died following a fire at a home where methamphetamine was being manufactured.

Neibi Brito was initially set appear in Gwinnett County Magistrate Court at 1:30 p.m. Wednesday to face a felony charge of trafficking in methamphetamine. A new court date has not been set.

Gwinnett County police are still looking for Ivan Gonzalez, a resident of the Lilburn home who is charged with murder in connection with the deaths of Isaac Guevara, 4, Ivan Guevara, 3, and 18-month-old Stacy Brito. Now, the sheriff has launched an investigation into how his department handled Gonzalez's case, the Associated Press is reporting.

Investigators said the children died of severe burns and smoke inhalation shortly after bystanders rescued them from the second story of the burning house on Thursday.

Gwinnett County Sheriff's Office spokesman Stacey Bourbonnais the department also is investigating why Gonzalez failed to show up on a federal immigration database after an earlier arrest.

Bourbonnais said Gonzalez's name should have showed up on the federal Secure Communities system after he was arrested using an alias on Feb. 10. But she said the system had been offline for three weeks.

--The Associated Press contributed to this report.