Police in Munich are investigating a mystery: More than 1,000 stickers were put on gravestones and wooden crosses at three cemeteries in the German city, without any indication of where they came from or why.

German police are investigating after over 1,000 QR-code stickers were slapped onto graves across three cemeteries in Munich. The small stickers, when scanned with a mobile phone, show the deceased person’s name and their location in the cemeteries.

Cemeteries in Munich allow QR codes as memorials on headstones, Mr. Hoerauf said, and for more than a decade, people whose loved ones are buried in cemeteries around the world have uploaded photographs and other digital keepsakes to create online memorials that can be viewed via QR code.

Some social media users claimed that it was a viral marketing stunt while others suspected vandals or even a tech-savvy artist making a statement.

The local police have requested those who have witnessed anybody putting the stickers on the graves in Munich to reach out to the respective cemetery's administration.