Lopez confirmed that two children were in the house, but she didn't know their ages. A motive for the attack has not been released
The attack occurred in a sprawling complex of brick row apartment buildings next to warehouses and older detached homes.
Police were also investigating a check cashing store robbery earlier Thursday in which two men used a flammable liquid to set a small fire at a customer service window. In that instance, the suspects used a similar pump sprayer, Lopez said.
No one was hurt, and it wasn't known if the incidents were related. The store is about three miles east of the apartment complex.
An employee at the check cashing business said Friday she was not allowed to comment about the robbery. Burn marks were still visible on the glass that separates employees from customers, and a wall behind the clerk's desk was blackened by flames.
Associated Press writer P. Solomon Banda contributed to this report.