In 2012, Illinois' Jack Daniel McCullough was convicted of the 1957 murder of his Sycamore neighbor Maria Ridulph, 7, appearing to wrap up the country's oldest cold case ever to go to trial. Four years later on March 24, a prosecutor announced McCullough had been wrongly convicted as he was actually 40 miles away from Sycamore at the time of the crime, reports the Daily Chronicle. A new lead happened to arrive in the mail that same day. A typed, unsigned letter sent to Illinois state's attorney Richard Schmack gave the name of a potential suspect, now the focus of an active investigation, reports CNN. Illinois State Police say they've "conducted an investigative workup" and are trying to locate the individual.
The revelation comes via a police affidavit in response to a public-records lawsuit from McCullough's son-in-law, who's asking for the case files to be released. What has been revealed about the case: A man who identified himself as "Johnny" approached Ridulph and a friend as they were playing outside on Dec. 3, 1957, offered to give them piggyback rides, then disappeared with Ridulph as her friend ran home to get mittens. Ridulph's body was found five months later near the Iowa border. The suit specifically asks for any late 2010 files related to that friend, Kathy Chapman, "in association with the investigation" of McCullough. The affidavit states that releasing those 23 pages "could impair [the] current investigation into the March 24th anonymous tip" as they contain information that only Chapman and the killer know. (This 1993 cold case still baffles officers.)