Prosecutors have arrested a key figure and relative of Justice Minister Cho Kuk believed to be involved in the private equity fund the minister's family invested in.

The minister's cousin, also surnamed Cho, was arrested at Incheon International Airport on Saturday morning on charges of embezzlement.

Cho was immediately escorted to the Seoul Central District Prosecutors Office and is being questioned on various allegations concerning the equity fund.

He is suspected to be the actual operator of the firm called Co-Link Private Equity which manages the fund in question.

He left the country in late August when speculations involving the then minister nominee surfaced.

Cho was initially known to be in the Philippines and then rumored to have left for Vietnam in recent days.

The arrest comes as prosecutors are widening their probe into corruption allegations surrounding the minister.