On Friday, U.S. officials announced the arrest of Christopher Ahn, a U.S. Marine veteran implicated in the raid of the North Korean embassy in Madrid this past February. During the raid, embassy staff were restrained, with some reported to have been beaten, before the 10-person group left with a variety of stolen electronics, including computers and cell phones.

Ahn was first taken into custody by U.S. Marshals on Thursday, according to an agency statement. He stands accused of being one of 10 individuals who carried out the February raid only days before President Trump’s ill-fated Hanoi summit with North Korea’s Kim Jong-un. Responsibility for the raid has been attributed to a group known as the Cheollima Civil Defense, also known as Free Joeon, an organization that calls for the overthrow of North Korea’s supreme leader. The group became known shortly after the assassination of Kim Jong-un’s half brother, Kim Jong-nam.

Jong-nam was said to be first in line to take control of the North Korean state following his father’s death, but an embarrassing incident involving traveling out of the nation using a forged passport to take his family to Tokyo Disneyland cost him his father’s favor. Many within the North Korean populace still held Kim Jong-nam in high esteem, though, making his presence a threat to Kim Jong-un’s dubious leadership. Shortly after Jong-nam’s assassination (which has been tied directly to Kim Jong-un), the Cheollima Civil Defense announced that a prominent member of this organization, Adrian Hong, had repeatedly asked Jong-nam to serve as a resistance leader against his half brother.

“He asked Kim Jong-nam multiple times to serve as the insurgent leader, only to be met with rejection,” said Kim Jung-bong, a South Korean academic who worked at Seoul’s National Intelligence Service until 2007.

Hong’s apartment was raided on Thursday as well, though reports indicated that he was not there at the time of the raid. The Justice Department has thus far declined to comment on the state of its investigation. Hong’s attorney issued a statement soon thereafter suggesting that the U.S. may be looking to extradite suspects to North Korea.

“The last U.S. citizen who fell into the custody of the Kim regime returned home maimed from torture and did not survive. We have received no assurances from the U.S. government about the safety and security of the U.S. nationals it is now targeting,” said Lee Wolosky, Hong’s attorney, in a statement.

Ahn’s case remains sealed, with no announcements made to the public regarding the charges he faces. The public defender assigned to Ahn has thus far also declined to comment to the press. Because Ahn’s arrest was made under a provisional warrant out of Madrid, an extradition hearing would make a legal judgment regarding Ahn’s extradition to Spain to face charges for any role he may have played in the raid. Generally speaking, an American ruling to extradite Ahn to Spain to face charges would not equate to a legal right to extradite him from Spanish custody and back to North Korea.