An off-duty Orleans Parish sheriff’s deputy opened fire on an unarmed shoplifting suspect in the parking lot of an Algiers Wal-Mart on Tuesday but managed to strike only a bystander’s car.

Lt. Frank Serio feared that Austin Thompson, 34, was reaching for a gun — it turned out to be a cellphone — and let loose four shots about 3 p.m., officials said. None of the bullets hit their target and no one was injured, but a woman’s car was damaged as she tried to leave the scene.

Police said Thompson later claimed he was attempting to commit suicide by drawing fire from the deputy.

Thompson will be booked on counts of aggravated assault of a police officer and attempted theft, police said.

The assault charge stems from the fact that Thompson made Serio fear for his life, New Orleans Police Department 4th District Cmdr. Shaun Ferguson said.

Ferguson said a store employee recognized Thompson, a former employee at a Jefferson Parish Wal-Mart, inside the store in the 4000 block of Behrman Place and suspected he was attempting to steal cellphones valued at $7,000. Serio, who was working a paid security shift at the store, followed Thompson out to the parking lot and confronted him.

Sheriff’s Office spokesman Philip Stelly said Thompson reached into his waistband as he crouched in between parked cars and pulled out a shiny object. Believing that object to be a gun, Serio fired four times, Stelly said.

After the shots were fired, Thompson knelt down on the ground to surrender and was taken into custody. Investigators then discovered the object was a phone.

The shooting did not appear to cause much of a commotion. Shoppers at the Wal-Mart emerged afterward to see police cars and wondered what had happened. Employees at a nearby gas station and dollar store were equally surprised, saying they hadn’t heard any shots.

Tuesday’s event was the third shooting incident in recent weeks involving an Orleans Parish Sheriff’s Office deputy. On Memorial Day, a deputy conducting traffic stops at Canal and Rampart streets shot at a man who allegedly tried to hit him with a car. The driver escaped without being hit.

Then, on July 7, Deputy Paul Sylvester allegedly went on a crime spree across the city, at one point shooting at a car full of people in the Lower Garden District. He was fired the next day.