Prosecutors with search and seizure warrants raided Thursday several places that include the head office of the duty-free unit of Lotte Group and the home of the daughter of the retail giant’s founder Shin Kyuk-ho.

They said Shin Young-ja is suspected of offering favors -- in return for kickbacks -- to Jung Woon-ho, a convicted businessman who approached her through a middle man to get his cosmetics brand into Lotte duty-free shops.

We believe that there should be no stone left unturned in the prosecution’s investigation into the Jung scandal, which started with the conviction of the CEO of Nature Republic who is now serving a prison term for illegal gambling charges.

But we also believe the key question the Jung case has raised is whether Jung’s counsels -- former senior judge Choi You-jeong and former senior prosecutor Hong Man-pyo, who received huge sums of money from the corrupt businessman -- used their personal connections with former colleagues to get him a lighter punishment. 

When looked at from this perspective, it raises questions as to why the prosecution has yet to launch an official probe into suspicions involving the serving judges and prosecutors. The probe into Lotte should not distract from this core element of the investigation. Choi and Hong have already been put into custody for pocking illegal money from Jung.

There is already sufficient circumstantial evidence, such as records of contacts including telephone conversations and meetings, which indicate that Choi and Hong used personal ties to influence their former colleagues regarding the legal punishment of Jung.

If not, Jung would not have been able to avoid indictment twice -- in 2013 and 2014. When he was finally indicted last year, he was charged only with illegal gambling, not embezzlement that carries heavier punishment. The high court’s decision to shorten Jung’s original one-year prison term to eight months was also put into question.

It was only after public criticism mounted that the prosecution decided to raise embezzlement charges against Jung, accusing him of diverting about 14 billion won ($11.7 million) of company funds. This will keep Jung, who otherwise could have been freed on Sunday at the end of his eight-month prison term, in detention.

It is important for people like Jung to be brought to justice. The bigger thing at stake here is, however, whether the prosecution can prove corrupt ties between the counsels and their former colleagues.

Given past experience, it might be a tall order for prosecutors to try to get to the bottom of the case, which could result in the jailing of colleagues and damage to their own reputation. Appointment of an independent counsel would then be inevitable.