Police in South Wales employed a pioneering fingerprint technique which led to the conviction of a drug ring. An image of a man holding ecstasy tablets in his palm was discovered on the cell phone of one of the detained suspects. It was then sent to the Scientific Support Unit of the South Wales Police. The incriminating photo emerged following a tip-off which indicated drug deals were taking place in a house in Bridgend. The photo was part of a stream of WhatsApp messages dating back several months.
Source: https://www.bleepingcomputer.com/news/government/eleven-drug-convictions-after-extracting-fingerprint-from-whatsapp-photo/