Police said Tuesday that they have failed to determine how the fugitive shipping tycoon blamed for April's ferry disaster died, deepening the mystery surrounding the final days of the country's most wanted man.

The body of Yoo Byung-eun, a 73-year-old billionaire whose family owns Sewol operator Chonghaejin Marine Co., was found on a remote hill just outside of the southern city of Suncheon, about 415 kilometers south of Seoul, on June 12 amid a nationwide massive manhunt.

Authorities had sought Yoo -- a religious figure and ex-convict -- believing that his alleged corruption may have contributed to the April 16 disaster that left more than 300 people, mostly high school students, dead or missing.  

"No evidence was discovered to determine whether Yoo Byung-eun's death was caused by a crime," Baek Seung-ho, a senior police officer probing the case, said at a press briefing.

After conducting a second autopsy and doing various scientific tests, police said it is likely that Yoo died before June 2.

The inconclusive result comes after the state forensic lab had earlier concluded that it was impossible to determine Yoo's cause of death as his body was too decomposed.

Also police came under fire for failing to locate Yoo's whereabouts for nearly three months or identify his body, even after expending massive financial and personnel resources in the investigation.

The Sewol ferry capsized off southwestern South Korea on April 16 after making a sharp turn. So far, 294 people, mostly high school students, have been found dead, with 10 missing and presumed dead. (Yonhap)