Prosecutors investigating the Sung Woan-jong payoff scandal raided last Friday the home of a former Saenuri Party official suspected of receiving money from the late tycoon before the 2012 presidential election.

The man, who was a deputy spokesman for President Park Geun-hye’s presidential campaign team, was also called in for questioning by investigators for the second straight day Saturday.

The actions taken against him are part of the prosecution’s investigation into allegations that Sung, who ran the construction firm Keangnam Enterprises, gave illegal funds to Park’s campaign managers.

A senior Keangnam executive told prosecutors that he gave 200 million won ($180,000) to the former Saenuri official before the 2012 election campaign.

What is hard to understand is that prosecutors started the full-fledged investigation on him more than one month after getting the testimony from the Keangnam executive.

Normally, prosecutors would not spend as long as one month verifying testimony like that provided by the Keangnam executive. One month is enough time for him to tamper with the evidence, if any.

This raises suspicion that the prosecution lacks the will to get to the bottom of Sung’s allegations regarding Park’s campaign funds.

There is one more thing we find hard to understand: Prosecutors sent out written questions to six people whose names Sung mentioned before he committed suicide.

All six are close associates of President Park and, except in the case of current Blue House Chief of Staff Lee Byung-ki, Sung disclosed specific amounts of money he allegedly gave to each of them.

Of them, three ― Rep. Hong Moon-jong, Incheon Mayor Yoo Jeong-bok and Busan Mayor Suh Byung-soo ― were top managers of Park’s 2012 presidential campaign, and Sung made it clear that he gave money ― 200 million won to 300 million won ― to help them run the campaign.

This more than constitutes sufficient circumstantial evidence to take actions promptly, like tracing their financial accounts, searching their homes and offices and summoning them for questioning.

Without taking any of these actions, prosecutors simply sent out written questions to the six people. We know that prosecutors use written inquires in cases for which they do not have strong evidence to press charges.

Prosecutors said they would think about their next steps after receiving the answers from the six politicians. But it is apparent that they are bringing the case to a close without indicting any of them.

It is more sad than outrageous that once again, our state prosecution has turned out to be a paper tiger. What saddens us even more is that the opposition, which is also suspected of taking campaign money from Sung, may not pursue the case, either.