Two female followers of the deceased Yoo Byung-eun gave up themselves up to law enforcement authorities on Monday.
According to the Incheon District Prosecutors' Office, the two aides are Kim Myung-sook, in her 50s, and Yoo Hee-ja, the wife of the sunken ferry owner's chauffeur Yang Hoi-jeong.
The three figures -- Kim, Yoo and Yang -- have been suspected of masterminding the 73-year-old Yoo Byung-eun's escape after the April 16 sinking tragedy.
Investigators, however, have yet to determine the whereabouts of Yang Hoi-jeong, according to the prosecution and state police agency.
Pundits shared the view that chauffeur Yang may hold the key to revealing the exact cause of the late Sewol owner Yoo Byung-eun's death.