Jose Arreola walked into a Southern California gas station to buy Mentos on a Friday night in March and still can’t shake off what happened next. After he paid for the mints and placed them in his left jacket pocket, an off-duty police officer behind him pulled out his handgun, pointed it at his feet and accused him of stealing them.

“It made me angry,” Mr. Arreola, 49, said on Monday. “I felt this fear and thought of my wife. My wife might become a widow tonight.”

The night started when Mr. Arreola, who was on his way to a club with his wife, pulled into a Chevron station in Buena Park in Orange County, Calif. He got $60 out of an A.T.M., then remembered that his wife had asked for mints.

Standing in front of the cashier, Mr. Arreola scanned a row of candy bars, sweets and gum before reaching for a roll of Mentos. “How much are these?” Mr. Arreola asked the man behind the counter. The cashier told him they were $1.19.