A Michigan father, who was nearing the end of his prison term for unlawfully restraining his three young sons, will continue to be incarcerated.

John Skelton, 53, now faces murder charges for the deaths of his sons — Andrew, aged 9, Alexander, aged 7, and Tanner, aged 5. These charges come more than ten years after the boys were last seen alive. Fifteen years ago, following Thanksgiving, Skelton failed to return the boys to their mother. Instead, he spun various tales about their whereabouts, including a story that he had handed them over to an “underground sanctuary” to be cared for by unknown individuals. After the boys were legally pronounced dead, authorities accused Skelton of murdering them and concealing their bodies.

Currently, Skelton is detained at the Lenawee County Jail with a bond set at $60 million.

The murder charges were disclosed on November 12, just weeks prior to Skelton’s anticipated release from prison, where he was serving time for the false imprisonment of his sons. He was convicted in 2011, roughly a year after the boys disappeared. Until last week, he had not been formally charged in relation to their deaths.

According to a report by WTVG, a local ABC affiliate, police conducted an interview with Skelton in prison earlier this month, hoping he might reveal new details before his release. However, as stated in an affidavit WTVG obtained, Skelton remained “uncooperative” and offered no new insights.

Further, the affidavit said that Skelton “consistently misled” authorities ever since the boys went missing in 2010. The purported “underground sanctuary” that Skelton claimed “[kept] children safe from harmful situations” does not exist, police said. While specifics about the new evidence were not included in the affidavit, police said that Skelton made conscious attempts to conceal his sons’ bodies to prevent anyone from finding out how they died.

According to the affidavit, Skelton searched the internet for different ways to kill people during November 2010, the time period leading up to the Thanksgiving the boys disappeared. When Skelton’s ex-wife, Tanya Zuvers, went to get her sons after the holiday was over, she found out that they were gone. Skelton was also hospitalized after he injured himself during a failed attempt to take his own life. When he provided several different stories about where the boys were, Zuvers reported them missing.

Police said that Zuvers asked to end her marriage to Skelton two months prior and was seeking sole custody of the children.

Skelton was charged with three counts of open murder and tampering with evidence. His next court date is scheduled for Nov. 24.