The thieves broke into the house last April and immediately decided to place an anonymous tip with the police, dropping off the evidence through a station letterbox, the Süddeutsche Zeitung reported on Friday.
But it was not until September that police in the Freital area of Saxony, eastern Germany, turned up at the house from which the hard drives were taken and stumbled upon a sex offender who they then linked to 89 counts of sexual assault between 2009 and 2012 alone.
Identified only as Hans-Jörg H. by the Sächsische Zeitung, the state prosecutor working on the case believes his main victim was his daughter, whom the 60-year-old engineer may have began abusing in 2008 when she was a four-month-old baby.
He admitted to the offences and the case opened this week in the Dresden regional court.
The two burglars who handed the stolen goods containing the evidence remain at large and police have no clues as to their identities.