South Korean police have raided the Seoul headquarters of Starbucks' local operation as part of an investigation into a marketing campaign that has been widely criticized for allegedly defaming the country's pro-democracy movements.

Investigators searched the company's offices in southern Seoul on Tuesday, according to police statements made Wednesday. South Korean media reported that investigators also targeted the residences of Starbucks executives. The specific details of the investigation have not been released by authorities.

The controversy erupted when Starbucks Korea launched a campaign promoting stainless-steel tumblers branded as "SS Tank," designating May 18 as "Tank Day." This date marks the anniversary of the 1980 pro-democracy uprising in Gwangju, a movement brutally suppressed by South Korea's then military-backed government. Official records indicate approximately 200 people were killed during the Gwangju crackdown.

The campaign's slogan, "Thwack it on the table!" also drew criticism, as many interpreted it as a reference to a notorious 1987 police statement that attempted to conceal the torture death of student activist Park Jong-chol. Authorities at the time falsely claimed Park died after investigators "hit the desk with a thwack."

Public backlash was swift, leading Shinsegae Group, which holds a 67.5% stake in Starbucks Korea, to cancel the campaign within hours. The chief executive of Starbucks Korea was subsequently fired, and Shinsegae Chairman Chung Yong-jin issued a televised apology. In an effort to address the issue, Starbucks Korea closed all its stores nationwide on June 22 for mandatory history and social sensitivity training.

The police investigation was initiated following complaints filed by relatives of the victims of the Gwangju crackdown. South Korea transitioned to a genuine democracy in 1987, a year marked by massive pro-democracy demonstrations that compelled then-authoritarian President Chun Doo-hwan, who led the Gwangju suppression, to accept constitutional revisions introducing direct presidential elections.