President Yoon Suk Yeol, who has already been impeached, became South Korea’s first sitting leader to be detained after weeks of openly defying authorities.

The development, which followed a failed arrest attempt earlier in January, deepens the fallout from his short-lived declaration of martial law last month.

South Korean investigators arrested impeached President Yoon Suk Yeol on Wednesday for alleged insurrection over his bid to impose martial law, after weeks of defiance and claims by Yoon and his lawyers that the arrest warrant was invalid.