HOUSTON (AP) — A refrigerator, not a stove, might be to blame for causing a fire at a Texas home day care that killed four children and injured three others, an engineering expert told jurors Wednesday during the owner’s murder trial.

Prosecutors allege that Jessica Tata had hot oil cooking on a stove at her day care when she left the children alone to go shopping at a nearby Target store. But Tata’s defense attorneys have told jurors she didn’t intend to harm the children, who ranged in age from 16 months to 3 years old, and that the February 2011 fire was not caused by anything their client did.