Ferguson was convicted on the testimony of Charles Erikson in the 2001 murder of Columbia Daily Tribune sports editor Kent Heitholt.
Erickson later recanted his story, but so far no appeal has been granted in the case.
KRCG 13 received a document with more than 100 pages that details the latest appeal to the Western District Court.
Teresa Snow spoke with Ryan's father, Bill Ferguson, Friday night, who said that the document boils down to arguments that more investigation should have gone into another man, Michael Boyd.
Boyd was the last person to see Heitholt alive. The document also alleges that then-prosecutor Kevin Crane made critical errors when coaching a witness to commit perjury and by not revealing evidence that would have helped the defense.
Click here to see the petition for writ of habeas corpus (if the document is not displaying correctly, you can download it to fix it).