Upholding a lower court ruling, a Seoul appeals court on Thursday acquitted a former Seoul police chief of charges that he impeded a police probe into a high-profile election-meddling scandal.

The scandal centers around allegations that the nation's intelligence agency meddled in the 2012 presidential election by swaying public opinion in favor of President Park Geun-hye, the then ruling party candidate.

The Seoul High Court delivered a not-guilty verdict to Kim Yong-pan, the former chief of the Seoul Metropolitan Police Agency (SMPA), citing a lack of evidence and the credibility of the testimony from a key witness.

Kim was indicted on charges of abusing his authority to cover up the case by deliberately hiding key evidence alleging that the National Intelligence Service (NIS) systematically intervened in the presidential election.

The 56-year-old former SMPA chief was further charged with violating the Public Official Election Act by allegedly ordering his subordinates to reduce the scale of the scandal and announcing a downsized outcome of the investigation into the election scandal.

"There is no clear evidence to acknowledge that (Kim) attempted to cover up the case and suspicions surrounding the NIS," Judge Kim Yong-bin said in his ruling.

Charges against Kim were brought to attention after Kwon Eun-hee, a lead investigator on the case at the time, claimed that she could not fully look into the case due to immense pressure from her superiors, including Kim.

"The court also does not acknowledge the credibility of witness Kwon Eun-hee's testimony," the judge said, adding that Kim's acts cannot be judged as campaign activities.

In a related matter, a Seoul court on Thursday convicted a senior SMPA officer of charges that he destroyed key evidence in the scandal.

The Seoul Central District Court sentenced the officer, only identified by his surname Park, to nine months behind bars for destroying computer files stored at the SMPA headquarters ahead of a prosecution raid in May 2013. (Yonhap)