A North Korean flag waves over the North Korean Embassy in Madrid, Spain, March 27, 2019. Getty

Madrid -- Spain has issued at least two international arrest warrants for members of a self-proclaimed human rights group who allegedly led a mysterious raid at the North Korean Embassy in Madrid last month and offered the FBI stolen data from the break-in. A National Court judge who lifted a secrecy order in the case Tuesday said an investigation of the Feb. 22 attack uncovered evidence that "a criminal organization" shackled and gagged embassy staff members before escaping with computers, hard drives and documents.

The intruders also urged North Korea's only accredited diplomat in Spain, business envoy So Yun Sok, to defect, Judge Jose de la Mata said in a written report on the Spanish investigation. So refused to do so and was gagged, according to the report.

The assailants identified themselves as "members of an association or movement of human rights for the liberation of North Korea."

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That group is the Cheollima Civil Defense, 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 from North Korea.

De la Mata identified citizens of Mexico, the United States and South Korea as the main suspects being investigated on charges that include of causing injuries, making threats and burglary. He named Adrian Hong Chang, a Mexican citizen living in the United States, as the break-in's leader.

Alleged FBI outreach

Hong Chang flew to the U.S. on Feb. 23, got in touch with the FBI and offered to share material and videos with federal investigators, according to the court report. The document did not say what type of information the items contained or whether the FBI accepted the offer.

The FBI said in a statement that its standard practice is to neither confirm nor deny the existence of investigations. The agency added that "the FBI enjoys a strong working relationship with our Spanish law enforcement partners."

An official with Spain's National Police who wasn't authorized to be named in media reports confirmed to The Associated Press that arrest warrants were issued for Hong Chang and one other suspect. No one had been charged as of Tuesday.

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

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.

The raid

Spanish police learned about the break-in after the wife of an embassy employee escaped by jumping from a window. When officers went to check on the situation, Hong Chang allegedly greeted them at the door and pretended to be a diplomatic official, the investigation found.

He sent the officers away with assurances everything was fine, paving the way for the invading group to make a getaway in the embassy's cars.

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."

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 the Madrid embassy.

The timing of the incident, which happened less than a week before a high-stakes U.S.-North Korea summit on denuclearization derailed in Hanoi on Feb. 28, led to speculation the incursion was carried out to obtain data related to North Korea's former ambassador to Spain.

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

Asked if Washington had any connection to the embassy break-in, U.S. State Department spokesman Robert Palladino answered, "The United States government had nothing to do with this."

Palladino 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."

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

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. None of the suspects were thought to be still in Spain, the judge wrote.

Spanish authorities tried to keep information about the attack from becoming public until Spain's El Confidencial news site revealed some details on Feb. 27.

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

The group said the video was filmed recently "on our homeland's soil," wording that would accurately apply to the North Korean Embassy in Madrid.