The prosecution has been driving investigations into suspected power abuses in past administrations too quickly. It rushes requests for arrest warrants.

Last week, the court rejected the prosecution’s requests for arrest warrants for retired Supreme Court Justices Ko Young-han and Park Byong-dae, suspected of abusing their power as chief judicial administrators during the days of President Park Geun-hye’s rule.

Throwing out the request, the judges cited that there were no concerns about destruction of evidence or fear of flight. Among others, they noted that suspected collusion between the ex-justices and an arrested former deputy chief of court administration was unclear. The court effectively told the prosecution to present convincing evidence if it wants the ex-justices arrested.

Of course, the rejection of a request for arrest warrant does not necessarily mean the suspect is innocent. It just means there is no need to arrest the suspect.

The Korean law on criminal litigation makes it a principle to investigate a suspect with as little physical restraint as possible. Arrest of a suspect should be requested only exceptionally.

The prosecution needs to look back on whether it has made light of the principle to match up to President Moon Jae-in’s signature drive to dig up abuses in the past governments and punish those involved. It must refrain from requesting arrest warrants habitually even when there are no concerns about destruction of evidence and fear of flight.

Investigation of evils in past administrations has been going on for more than a year and a half. Hundreds of raids have been made thus far. Nearly 30 former government officials of vice minister level and above are reportedly being tried.

If the prosecution investigated suspicions of a few years ago only to find no smoking gun, then it goes several more years back and combs through old incidents. If a suspect is released after arrest, it searches for new suspicions, related or unrelated, to request an arrest warrant again.

Kim Kwan-jin, former chief of the National Security Office under Park, was arrested on suspicions of masterminding a covert operation by the Cyber Warfare Command to post online comments apparently to interfere in politics. Later, he was released on bail. Then the prosecution conducted additional investigations and requested the arrest of Kim again. But the request was rejected.

A strong push for investigation into the past governments has produced side effects.

Lee Jae-su, retired commander of the Defense Security Command, took his own life Friday.

The prosecution requested an arrest warrant for him on suspicions of ordering the military intelligence unit to spy on the families of those who died in the Sewol ferry sinking, but the request was thrown out four days before his suicide.

If the military kept the bereaved families under surveillance to serve a political purpose, it should be condemned. Still, investigation and legal punishment must be based on solid evidence.

In November last year a senior prosecutor also took his life before the court was to rule on the request for an arrest warrant for him on suspicion of obstructing the prosecution’s investigation into an operation by the National Intelligence Service to post online comments intent to influence public opinion. The prosecutor was said to have begrudged being falsely accused.

A week earlier, a lawyer belonging to an NIS task force died by apparent suicide after being investigated by the prosecution on the same suspicions as the prosecutor who took his own life faced.

A senior executive of a defense contractor similarly took his life in September last year while the company was being investigated over allegations of management irregularities. But such irregularities were ultimately not found.

It is important to investigate past wrongdoings and improve related systems.

But if those who worked for past administrations ideologically different from the current one are persistently investigated, arrested and punished, suspicion of political retaliation is inevitable.

How many more sacrifices should be made to stop investigations into past regimes from going too far?