“Ultimately, beyond everything else, we took a phone and looked at everything on it – we knew it had a hand with drugs on it,” South Wales police officer Dave Thomas told BBC. “These guys [the dealers] are using the technology not to get caught and we need to keep up with advancements.”

The dealer in question had sent the photograph, which contained a number of pills, to potential customers via WhatsApp. While his direct fingerprint was not visible in the picture, the middle and bottom of a finger were — and that was enough to point the cops in the right direction.

Photo: South Wales Police

Authorities were able to download the photo and messages from his phone. While WhatsApp’s end-to-end encryption feature makes it difficult to access photos and messages remotely, officials can fairly easily recover them from senders’ or recipients’ phones.

“While the scale and quality of the photograph proved a challenge, the small bits were enough to prove he was the dealer,” said Thomas. “It has now opened the floodgates and when there is part of a hand on a photograph, officers are sending them in.”

“These are all advancements in the digital world – they provide lots of questions we need to provide answers for.”

This incident should serve as a wake-up call to authorities in all countries: You never know what you can find on a phone, even from encrypted messaging services. Thomas reported that his department will, going forward, look more closely at photographs on seized phones for potential evidence.

This method certainly can’t catch all criminals, as most photos won’t display a clear photo of a full fingerprint, but it’s another important tool to help police catch criminals more efficiently and accurately.