MILPITAS — A woman has been arrested after allegedly planting a smoke bomb in a Walmart last August as a “trial run” to distract employees during future thefts, authorities said.

Fremont resident Kali Lynn Farrell, 25, was booked into Santa Clara County jail in September in connection with the incident that forced the store’s evacuation. Authorities kept the arrest quiet until now to investigate any related bomb threats, Milpitas Police Department Sgt. Steve Parodi said Monday in a news release.

Kali Lynn Farrell, 25, allegedly planted the bomb as a “trial run” to distract employees during future thefts, Milpitas police said. 

Just after 4:30 p.m. on Aug. 9, a Walmart employee at the Ranch Drive and McCarthy Boulevard location in Milpitas called 911 to report the smell of smoke, Parodi said. Inside the store, firefighters found a plastic object with an exposed orange detonation cord, wrapped in black electrical tape.

Suspecting the device was a smoke bomb, authorities evacuated the Walmart and called in bomb squads from San Jose Police Department and Santa Clara County Sheriff’s Office. About six hours later, the teams rendered the device safe; it had been made with smoke balls and a wireless detonation system.

Over the next month, Milpitas investigators gathered surveillance footage and physical evidence that ultimately linked Farrell to the scene, Parodi said. She allegedly planted the bomb to test out a method of distracting employees during future thefts.

Farrell was arrested out of her home on Sept. 25 on suspicion of arson and possession of an incendiary device. There are no related threats or other involved suspects, Parodi said.

Anyone with information on the incident may call the Milpitas Police Department at 408-586-2400, or anonymously at 408-586-2500.