WAUKEGAN, Ill. (CBS) — Waukegan police have re-opened the nearly 20-year-old investigation into the rape and murder of 11-year-old Holly Staker.

As WBBM Newsradio’s Mike Krauser reports, Waukegan police Chief Dan Greathouse tells the Lake County News-Sun the Staker murder is under review right now.

LISTEN: WBBM Newsradio’s Mike Krauser reports

Staker was fatally stabbed and sexually assaulted while babysitting two younger children on Aug. 17, 1992.

After nearly 20 years, the Staker case is now cold. Investigators had always thought they had the killer, Juan Rivera, who had confessed after a long interrogation, but whose DNA was not a match.

Rivera was convicted three times – in 1993, 1998 and 2009 – but his conviction was overturned each and every time.

This past Friday, Rivera walked out of Stateville Correctional Center in Joliet after being locked up for 19 years.

Rivera’s 2009 conviction was “unjustified and cannot stand” because of a lack of evidence tying him to Staker’s rape and murder, the 2nd District Appellate Court panel said in its 3-0 ruling in December.

Lake County prosecutors decided not to challenge the decision.