Busan police on Wednesday arrested three members of one of South Korea’s largest crime syndicates for blackmailing and extorting real estate properties worth millions from a local construction firm.

A leader of the Chilsung-pa, or Seven Star Mob, identified only by his surname Kim, and two other members were arrested on charges of extorting 23.3 billion won worth of land property rights by blackmailing the CEO of a local construction firm over his alleged embezzlement of company funds worth 38 billion won, according to the Busan Nambu Police Precinct.

Four other gang members were booked with the same charge without physical detention, reports Korea JoongAng Daily.

The CEO, identified by his surname Jung, was found to have paid 2.1 billion won in bribes to an unspecified number of local government officials to purchase reclaimed lands in Busan’s Nam District.

The police said they had earlier convicted Jung of fraud and were investigating who received the bribes.

The arrests is one of the highest-profile mob bust in Busan involving one of South Korea’s most notorious gangs.