( CNN) A federal appeals court has upheld a ruling that overturned the murder conviction of Brendan Dassey, who was featured in the Netflix series “Making a Murderer.”

The ruling differentiates a major victory for Dassey , now 27, whose confession became a key subplot in the series.

Dassey was convicted in 2007 in the slay of Wisconsin photographer Teresa Halbach. In 2005, Dassey, then 16, admitted to authorities that he assisted his uncle, Steven Avery, in raping and killing Halbach. Her charred remains were found on Avery family property in Manitowoc County.