Chun Woo-won, a grandson of late former President Chun Doo-hwan, was released Wednesday after being arrested the previous day for investigation over suspected illegal drug use.
Police released Chun at around 7:55 p.m., some 38 hours after he was apprehended at Incheon International Airport upon arrival from New York on Tuesday.
Police said they will probe him without detention in consideration that he confessed to his wrongdoings and voluntarily returned to the country for investigation.
Woo-won, a son of Chun's second son, Jae-yong, made headlines earlier this month for his revelations online and via media interviews about irregularities involving his family.
Chun Doo-hwan, who served as president from 1980-88 after seizing power in a 1979 military coup, is widely criticized for the bloody crackdown on the pro-democracy uprising in Gwangju in 1980, which left hundreds of people dead.
In a video uploaded online, the grandson called Chun a "slaughterer" and accused his family of allegedly using money from hidden assets.
In another YouTube video, Woo-won said he and his acquaintances have been using illegal drugs, and swallowed what he called ecstasy and other narcotics while livestreaming.
As early as Thursday, he plans to visit Gwangju and apologize to the victims of the 1980 crackdown.
Source: Yonhap News Agency