Photographing smartphone intruders. Every good journalist keeps a contacts list on their phone. It is a roll-call of confidential — sometimes highly confidential — numbers belonging to artists, executives, senior politicians and star footballers. And every careful reporter has a duty to keep that address book out of prying eyes. A curious, jealous colleague, for example, might use our absence from the desk to scroll through our contacts and lift the number of the President of the Republic. Or the phone could be stolen and end up in the hands of someone with malicious intent. There is a countermeasure for that risk, and it does two jobs at once. CrookCatcher — an app available for Android devices — lets you lock down access to your smartphone using familiar tools: a PIN, an on-screen pattern, or a fingerprint. The second feature is the most striking. Your phone will photograph anyone who tries to break through its defences but enters the wrong PIN or pattern. Intruders are caught on camera and exposed. And that is not all: the handset will email you the intruder’s photo, along with their approximate location.