Emergency personnel respond to a fire at a day care operated by Jessica Tata in Houston. Tata has been charged with reckless injury to a child involving serious bodily injury. (AP Photo/Houston Chronicle, Michael Paulsen, File)

HOUSTON (AP) — Investigators say a Houston day care operator who left the children she was watching alone was shopping when the deadly fire started at the facility. The blaze killed four children.

A probable cause affidavit made public Tuesday says surveillance video shows 22-year-old Jessica Tata shopping at a Target store about a mile away from the home at the time the fire began.

Investigators believe last week's fire was started by a stove top burner that had been left on.

Tata has been charged with reckless injury to a child involving serious bodily injury and has fled to her native Nigeria. Authorities are working to locate her.

Two of the injured children remain hospitalized but are stable and improving.