Yoo Dae-kyoon, the eldest son of Yoo Byung-eun, denied charges of embezzlement on Sunday, as judges are expected to issue an arrest warrant for the junior Yoo, allowing prosecutors to detain him for further questioning.
Police arrested Dae-kyoon on Friday, shortly after officials had confirmed that an unidentified body found last month was in fact that of the senior Yoo.
The Yoos had topped the police's most wanted list for more than 70 days.
With Dae-kyoon in custody, prosecutors are now hoping to discover the extent to which the Yoo family contributed to the ferry accident.
The 6,825-ton ferry Sewol sank in waters off Korea's southwestern coast on April 16, leaving more than 300 dead or missing. Most of those killed were teenagers on a school trip.
Prosecutors said the Yoos contributed to the ferry disaster by misappropriating funds of Chonghaejin Marine Co. that could have been used to strengthen safety standards on the Sewol such as increasing the number of regular emergency drills.
Chonghaejin Marine Co. was the operator of the Sewol. The Yoos are considered to be the de facto owners of Chonghaejin.
Authorities are focusing on finding answers to questions still shrouding the Yoo family's connections to the ferry disaster.
Where and for what purposes Dae-kyoon spent the more than 9.9 billion won ($9.6 million) he had allegedly embezzled from Chonghaejin is still unclear.
Dae-kyoon on Sunday admitted to receiving the money, but denied during questionings that he had taken it improperly.
Whether there were any other confidants who helped the Yoos flee the police is another key point for investigators. Dae-kyoon was found along with a female aide who is alleged to have accompanied the 44-year-old while he was on the run.
The authorities are also trying to identify anyone who might have had a reason to kill Yoo Byung-eun.
The cause of his death has eluded prosecutors, even after Dae-kyoon's arrest. The senior Yoo was found dead in a plum orchard in South Jeolla Province on June 12.
The identity of Yoo's body was confirmed on July 22, resulting in an abrupt end to a nationwide manhunt.
The National Forensic Service on Friday said it could not identify the cause of death largely because the body was badly decomposed.
Dae-kyoon has said he did not know of his father's death until his arrest.
Officials are investigating whether the 73-year-old billionaire committed suicide or was murdered. Forensic experts have ruled out poisoning and suffocation as the causes of death.