Police said Tuesday they began an investigation into allegations that the main opposition party engaged in massive manipulation of online opinion during past elections, including the 2007 presidential vote.

The cyber crime unit of the Seoul Metropolitan Police Agency said they were questioning party officials with the ruling Democratic Party who filed the complaints about the allegations.

The Liberty Korea Party is accused of having used a computer program to spread favorable news and jack up likes on Internet news comments from 2006 to 2014, during which it was called the Grand National Party and later the Saenuri Party.

The ruling Democratic Party filed a complaint on June 7 against the LKP a day after a newspaper report raised the allegations.

Police said they plan to get statements from those who worked for the election camps and were involved in the alleged rigging activities.

The allegations come amid a separate case of online comment manipulation involving an influential blogger known as Druking, who is allegedly linked to Kim Kyoung-soo, a close aide of President Moon Jae-in who last week was elected governor of South Gyeongsang Province.

A special counsel team has been formed to investigate the Druking case. Kim has denied any wrongdoing. (Yonhap)