AMPA (CBSMiami/AP) – A woman is accused of trying to build and detonate an explosive device inside a Tampa Walmart store.

Emily Stallard, 37, was arrested Saturday and charged with attempted arson of a structure, firebombing, contributing to the delinquency of a minor, child abuse and battery on an officer.

A security guard at the store noticed Stallard opening unpaid items including flammable materials, projectiles, and matches as she roamed through the store for more than an hour, an arrest report said. She had a child with her in the store, an arrest report said.

The security guard called the Hillsborough County Sheriff’s Office and also notified a Florida Fish and Wildlife officer who happened to be in the store at the time. The two men stopped Stallard just before she lit a wick, according to the report.

Investigators said Stallard spit at deputies as she was being loaded into a patrol car.

Sheriff Chad Chronister said Stallard had all the supplies she needed to cause mass destruction at her disposal.

“Had it not been for an alert off-duty law enforcement officer and a watchful security staff at Walmart, she may have followed through with her plans to cause an explosion inside the store,” he said.

Stallard remained in the Hillsborough County Jail on Tuesday.

(© Copyright 2020 CBS Broadcasting Inc. All Rights Reserved. The Associated Press contributed to this report.)