Washington (CNN) The head of a shadowy North Korean dissident group wanted by US authorities for his connection to the raid on Pyongyang's embassy in Madrid in February is in hiding from North Korean hit squads, his attorney told CNN on Monday.

Adrian Hong, the leader of the group, Cheollima Civil Defense, was not in his apartment when US marshals arrived on Thursday and his lawyer, Lee Wolosky, said he does not know his client's current location.

Video of the encounter shared with CNN by a source close to Hong shows six uniformed officers entering the unit and shouting "police" before beginning a search.

US authorities' interest in Hong is not publicly known, but another Cheollima Civil Defense associate, Christopher Ahn, was arrested Thursday in Los Angeles on a provisional warrant from Madrid, law enforcement officials said.

"He certainly fears for his safety. We do have reason to believe that North Korean hit squads have been dispatched to target Mr. Hong and perhaps others, and he is taking necessary steps to evade those hit squads," Wolosky said.

A Spanish judge last month said Hong was the ringleader of a group of ten men that carried out the embassy raid, which was described in court documents as a violent encounter.

According to Spanish court documents, Hong and other members of Cheollima Civil Defense beat and handcuffed embassy employees before taking a senior official to a basement room and urging him to defect from North Korea. Members of the dissident group escaped from the compound in embassy vehicles with two thumb drives, two computers and two hard drives, the court documents say.

Cheollima Civil Defense, whose stated goal is to overthrow the Kim regime, has confirmed it was behind the raid but denied it gagged or beat any of the embassy employees. They say they were invited into the embassy. Wolosky admits his client's involvement in the raid and said the group was not violent.

Wolosky described the group, which he said now wants to be called the "Provisional Government of Free Joseon," as a "magnet for defectors, who contact them in a variety of ways in all places around the globe."

Cheollima Civil Defense said in a statement last month that it shared "certain information of enormous potential value with the FBI in the United States, under mutually agreed terms of confidentiality." The FBI referred CNN to the Department of Justice for comment.

Ahn is in detention in Los Angeles ahead of a second hearing in federal court there Tuesday afternoon. It's not clear what he is charged with because his case remains under seal, but an online scheduling page for the case lists it as related to an extradition.

A public defender listed for Ahn has not responded to a request for comment.

Ahn is a former marine and previously worked with Cheollima Civil Defense when it helped move the son of Kim Jong Un's half brother to a safe site after Kim allegedly ordered that half brother's murder two years ago, according to Wolosky.

"He is an American hero," Wolosky said. "He deserves much better treatment than is currently being provided to him by the US government, which is housing him in federal detention in Los Angeles."

Wolosky said US authorities have given him "no assurances" about where they want to send Ahn, and called it "outrageous" that the US government appeared to be acting based on criminal complaints emanating from North Korea.

The Department of Justice would not comment on Ahn's or Hong's cases but a spokeswoman on Friday noted that the US would generally need to give permission for a country requesting the extradition of an individual to send that person to a third country.

"We are asking the president and the secretary of state, who has a direct role in the extradition process, to stop this and to stop it immediately. Let these men go back to serving their country, the United States, and to work toward a free and democratic North Korea as they have been doing. Let them go back to their families and let them go back to their service," Wolosky said.

CORRECTION: This story has been updated to correct the name of Adrian Hong.