, was questioned about the property deal the group made with Shigetake Ogata, 73, who formerly headed the Public Security Intelligence Agency, the sources said.
The agency's mission is to surveil groups engaged in subversive activities. Monitoring Chongryun is one of its priorities.
Ho is regarded as the de facto leader of Chongryun, which is nominally headed by 80-year-old So Man Sul.
The former chief of the intelligence agency has said he first met Ho in April at the office of lawyer Koken Tsuchiya, 84, a former chief of the Japan Federation of Bar Associations. Tsuchiya is representing Chongryun in a lawsuit filed by Resolution and Collection Corp., a state-backed debt collection agency.
Ogata, who is also a lawyer, said Ho suggested that Ogata's investment advisory firm, Harvest, buy the property and allow Chongryun to use the office until it can buy it back.
Ogata accepted the request. Under the deal, Chongryun would pay 350 million yen annually to Ogata's firm to continue using the facility, while retaining the right for five years to buy it back.
In late May, ownership of Chongryun's property was transferred to Harvest in a 3.5 billion yen deal that was not immediately accompanied by any payment.
Tsuchiya canceled the ownership transfer last week.
The prosecutors suspect the deal was a fake transaction intended to prevent the Chongryun property from being seized in a different legal case involving RCC.
For related stories:
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Chongryun HQ sold to ex-intelligence head
Chongryun ordered to pay RCC 63 billion yen