South Korean police conducted a raid on the national headquarters of Starbucks Korea on Tuesday amid an investigation into accusations that the company’s recent advertising campaign defamed activists killed during the 1980 Gwangju pro-democracy uprising. The raid, confirmed by a Shinsegae Group spokesperson, is part of an ongoing probe into allegations filed by civic groups and families of victims.

Starbucks Korea faced widespread criticism earlier this year following the launch of a promotion called “Tank Day” on May 18, which coincided with the anniversary of the Gwangju protests. The campaign introduced a series of large-capacity tumblers for coffee beverages, a move that many perceived as trivializing the historic democratic movement where at least 165 civilians lost their lives after military forces deployed tanks to suppress demonstrators.

Critics accused the company of disrespecting the memory of those who died during the uprising, which is regarded by many in South Korea as a pivotal moment in the nation’s democratization. The advertisement reportedly featured language that echoed phrases used by officials during the military regime to dismiss allegations that a student activist died under torture, further inflaming public outrage.

The complaint lodged by the civic group and bereaved families accuses executives from the Shinsegae Group, operator of Starbucks Korea, of defamation and insulting the victims and their families. “The Seoul police raided the headquarters of Starbucks Korea this morning as part of the ongoing investigation,” a Shinsegae spokesperson said.

In response to the backlash, Starbucks Korea publicly apologized and temporarily closed its more than 2,000 stores nationwide for a one-day staff education session in June to address the issue. South Korea represents the coffee chain’s third-largest market, after the United States and China, underscoring the significance of public sentiment in the country.

Authorities have yet to release further details about the investigation or potential charges related to the incident. The raid marks a heightened level of scrutiny on corporate practices involving sensitive historical events in South Korea.