Photos of stones found buried in the ground next to Lee Jae-myung's parents' graves in Bonghwa-gun, North Gyeongsang Province. (Lee Jae-myung's Facebook account)

Investigators have identified two suspects who allegedly desecrated the grave site of the main opposition Democratic Party of Korea's leader Lee Jae-myung’s parents, said officials at the North Gyeongsang Provincial Police on Sunday.

The two male suspects, aged 83 and 70, are accused of digging holes around the grave in Bonghwa-gun, North Gyeongsang Province and burying six stones painted with some Chinese characters in them. The 83-year-old is said to be known for his expertise in feng shui, or the geometric evaluation of land. The police have also identified two others who allegedly aided and abetted the act.

The police launched a probe into the case after Lee posted on Facebook photos of the desecrated graves of his parents and the stones found there. At the time, the former liberal presidential contender pointed to those practicing “black magic” as being responsible for it.

Investigators said the suspects appear to have acted out of a desire to help turn around Lee’s political fortunes. They said it was the 70-year-old suspect who had first suggested to “find a way to help Lee” to the 83-year-old suspect.

The police have acquired photos taken by the suspects on the day of the crime, as well as the tools used at the scene and forensic files.

"We plan to send the suspects to the prosecutor's office next week," a police official said.