Allegations of misconduct are mounting against Hong Man-pyo, a prosecutor-turned-lawyer suspected of having peddled his influence for a CEO of a cosmetics company convicted of illegal gambling.

As a prosecutor, Hong was highly competent. He made a name for himself with investigations into high-profile corruption cases involving heavyweight politicians and big corporations.

He became a lawyer in 2011 and soon emerged as one of the highest-earning lawyers. In 2013, he earned 9.1 billion won ($7.7 million) in reported legal fees.

But the high-powered lawyer is under investigation now for his alleged improper use of influence on prosecutors in defending Jung Woon-ho, the CEO of Nature Republic who was convicted last year.

Apart from Jung’s case, new allegations of influence-peddling have been raised against Hong. Investigators suspect he has been secretly engaged in a number of criminal cases without informing the court of his designation as counsel.

Under the Attorney-at-Law Act, when a lawyer accepts a case, they should submit a letter of designation of counsel to the relevant court or investigation agency by way of the local bar association with which they are affiliated.

But Hong is suspected of having clandestinely worked for a long list of businessmen facing criminal charges without submitting such letters. The list includes former Tong Yang Group chairman Hyun Jae-hyun and his wife, Ilkwang Group chairman Lee Kyu-tae, and Kim Kwang-jin, the former chairman of Hyundai Swiss Savings Bank.

One potent motivation that may have driven Hong to breach the regulation is tax evasion. A lawyer can evade taxes on their legal fees if they provide legal services without reporting their appointment as counsel.

Hong is suspected of having invested some of the money earned this way into real estate. He was found to own as many as 84 studio apartments, called “officetels” in Korea, and dozens of stores in cities in Gyeonggi and South Chungcheong provinces.

Investigators recently raided a real estate agency that manages Hong’s properties, suspecting that Hong might have sought to launder his illicitly earned money through this company.

In defending wealthy businessmen clandestinely, Hong is believed to have used his connections with prosecutors who were his juniors while he worked as a prosecutor.

In the Korean legal community, there is an outdated tradition in which incumbent prosecutors or judges grant private requests from their retired seniors.

This practice, called “jeon-gwan ye-u” in Korean, is known to be especially strong among prosecutors specializing in high-profile corruption cases involving politicians and corporations.

Hong is believed to have taken advantage of this unwholesome tradition when he defended Jung. The cosmetics company CEO was indicted three times for gambling abroad and violating the law on foreign exchange control. Hong helped his client clear himself of the charges in the first two cases. The third time, Jung was sentenced to one year in prison, but the term was shortened to eight months in an appellate trial last month.

The “jeon-gwan ye-u” practice is not only anachronistic but breeds corruption and ultimately ruins the legal system. Therefore, prosecutors should focus not just on Hong but on the fellow prosecutors and judges who joined him in making a mockery of justice.