MADRID -- Spain has issued two international arrest warrants for members of a self-proclaimed human rights group that allegedly led a mysterious attack on the North Korean Embassy in February before offering data stolen during the raid to the FBI.

National Court judge Jose de la Mata on Tuesday lifted a secrecy order in the case, announcing it had found evidence of various crimes, including trespassing, injuries, threats and burglary committed by “a criminal organization” at the embassy in a leafy northern Madrid neighbourhood. He identified a Mexican, an American and a South Korean as main suspects in the case.

The judge named Adrian Hong Chang, a Mexican national and resident in the United States, as the leader of a gang of 10 people who escaped on Feb. 22 after stealing computers and documents from the embassy, where they shackled and gagged its staff.

De la Mata said the assailants identified themselves as “members of an association or movement of human rights for the liberation of North Korea” and that they urged So Yun Sok, the embassy's business envoy and only diplomat, to defect. He refused to do so and was also gagged.

That group is the Cheollima Civil Defence, according to a U.S. official who spoke on condition of anonymity to discuss details of the incident. The shadowy activists have the self-declared mission of helping defectors of the North Korean regime.

The court document said Hong Chang flew to the U.S. on Feb. 23, where he got in touch with the FBI and offered to share material and videos with federal investigators. The Spanish investigation didn't say what the content of the material was, or whether the FBI accepted it.

The document added that most suspects were believed to be outside of Spain.

The FBI said in a statement that its standard practice is not to confirm nor deny the existence of investigations but added that “the FBI enjoys a strong working relationship with our Spanish law enforcement partners.”

A police spokesman who wasn't authorized to be named in media reports confirmed to The Associated Press that arrest warrants had been issued against Hong Chang and one other suspect.

No formal charges have yet been brought into the attack.

So, the North Korean diplomat, didn't respond to written questions from The Associated Press and declined to talk to reporters during a recent encounter outside his embassy in northwestern Madrid.

Others identified as part of the assailants' group were Sam Ryu, from the U.S., and Woo Ran Lee, a South Korean citizen. Their whereabouts and their hometowns weren't immediately known.

The South Korean Embassy in Madrid said it had no knowledge of the events and couldn't offer further comment.

The assailants purchased knives and handgun mock-ups when they visited Madrid in early February, according to the investigation, and later used them for the attack.

While in Madrid, Hong Chang also applied for a new passport at the Mexican Embassy, the investigation found, and used the name “Oswaldo Trump” to register in the Uber ride-hailing app.

The North Korean Embassy hasn't pressed charges in Spain, and officials in Pyongyang haven't officially commented on the attack.

Spanish police first found out about the incident after the wife of one of the embassy's workers managed to escape by jumping from a window.

When confronted by Spanish police officers who went to check on the embassy, Hong Chang posed as an embassy official and said everything was normal. That paved the way for the group's escape in the embassy's cars.

The attack's timing, barely a week before a high-stakes U.S.-North Korea summit on denuclearization derailed in Hanoi on Feb. 28, had led many to speculate that it was an attempt to obtain data related to the North's former ambassador to Spain.

Kim Hyok Chol, who was expelled from Spain in September 2017 following Pyongyang's sixth round of nuclear tests and missile launches over neighbouring Japan, has become North Korea's top nuclear negotiator with the U.S.

When asked if Washington had anything to do with the embassy raid, U.S. State Department spokesman Robert Palladino said Tuesday that “the United States government had nothing to do with this.”

Palladino also said that “regarding the specifics of what's going on, the Spanish authorities are investigating. The investigation is still underway. For any details on their investigation, I would have to refer you to Spanish authorities.”

Spanish authorities have kept the events of the embassy attack out of the public eye until Spain's El Confidencial news site first revealed some details on Feb. 27.

A police investigator with knowledge of the case told the AP that “this attack, whatever it is, would have gone unnoticed if it wasn't for the woman who escaped.”

Last week, the rights group that allegedly led the attack posted a short video on its website allegedly showing a man shattering against the floor portraits of North Korean late leaders Kim Il Sung and Kim Jong Il.

The group said the video had been filmed recently “on our homeland's soil,” in what could be a reference to the North Korean Embassy in Madrid.

AP writers Deb Riechmann and Matthew Lee in Washington contributed to this report.