The prosecution has decided to indict two key suspects in the Sung scandal, but without seeking to take them into custody.

The failure to detain former Prime Minister Lee Wan-koo and South Gyeongsang Gov. Hong Joon-pyo is disappointing all the more because it could be a prelude to the probe into six other people implicated in the payoff scandal.

Prosecutors said both Lee and Hong would be charged with receiving illegal political funds from the late Sung. Hong allegedly received 100 million won from Sung in 2011 and Lee took 30 million won in 2013. But they will not be charged with bribery, which is a more serious crime than violation of the Political Fund Law.

This is unacceptable because circumstantial evidence was stronger in the Lee and Hong cases than in that of the other six people. Not only did Sung provide details of when and how he gave money to Hong and Lee, but people around the three also offered testimonies backing their corrupt ties.

Moreover, both allegedly pressed or cajoled their associates and related people to tell lies regarding their contacts and relationship with the late Sung. Usually such attempts to tamper with or destroy evidence face heavy penalties.

This apparent leniency offers a stark contrast with the case of Sung’s former aides, two of whom were detained on charges of concealing or tampering with evidence.

That the prosecutors had different yardsticks was manifested by the fact that they tried to obtain a court warrant to detain Kim Jin-soo, a former deputy governor of the Financial Supervisory Service who is suspected of influencing creditor banks to aid Sung’s construction firm in return for kickbacks. The court turned down the request for an arrest warrant, citing insufficient evidence.

The Sung scandal sent a shockwave not only to the political community but also to Korean society as a whole because the central figure committed suicide after alleging that he gave huge sums of illegal money to influential people, including key members of the Park administration.

It has already unseated a prime minister and threatens the political lives of Hong and two more local administrators and associates of President Park. Besides, there are strong suspicions that part of Sung’s money went into the 2012 campaign funds of Park and the current opposition leader Moon Jae-in. There is every reason to get to the bottom of the scandal, that is, who received how much money from Sung and for what purposes.

Judging from the way the prosecution is dealing with Hong and Lee’s case, it is almost certain that we need to bring in an independent counsel.