TuesdayTips35

The mobile phone (not) the death of the crime novel
(Part 2)

Using modern technology in your books

Last week I wrote about the ways in which mobile phones are a technology that should be seen as an opportunity for modern writers, rather than as a constraint to their story telling. This week, I want to explore that in a bit more depth.

Location data
It is often said that we now carry a miniature tracking device around with us. That is true to an extent.
Unlike radios, phones do not connect directly to one another. Rather they need to connect to a cell tower, which then relays the signal (often in multiple steps) to the receiving handset. Therefore to make a call, send a text or use the internet, they need to be able to contact a cell tower - the same goes when receiving a call or text - if your phone has no signal, when it finally reconnects you will get any unreceived text messages or missed call notifications.


As a phone moves around it constantly connects and reconnects to the nearest cell tower. In areas with multiple towers, the phone will often be connected to several, choosing the one with the strongest signal. The strength of a signal decreases with distance, which means that it is possible to work out roughly how far from a tower a phone is. In a remote area with very few towers, this will be a large circle around the tower. In an area with more than one tower, there will be a circle for each connection. The handset will be within the region where the circles overlap, a process called triangulation. The more towers the phone connects to, the more precisely the phone can be located, sometime to just a few metres. In an urban setting, this should be very precise. In practise, lots of tall building and thick walls will impede this - consider this if you don't want your character's handset to be located too precisely.
Handily, phone networks keep a record of this data for at least 12 months, and again it can be obtained by a warrant. If you want to place a suspect at a location, at a specific time, then you can use this to a greater or lesser degree of accuracy.


However, this is only useful if your character is carrying their phone with them, or it is switched on. Might they leave it at home when they go out to commit their nefarious deeds, thus establishing an alibi? This could be disproven if a witness places them somewhere different to where their phone states they were. Perhaps they just turn it off? It's circumstantial, but if they never normally switch their phone off it seems a bit suspicious if the phone went off at the exact time the crime was committed...

GPS is a little different. The handset uses the distance from a series of orbiting satellites to triangulate its position. The satellites have no idea where the phone is and you can't "hack into" a GPS signal to work it out. However, the device may broadcast or record its location, and this could be picked up. Many online services like to know where your handset is, for legitimate or not so legitimate purposes. This can be turned off in your privacy settings (consider doing this - it's under location services on Google Android). Many apps make a log of where your handset has been. If police can unlock the handset, then they can access this log.
Intelligent, professional criminals will likely switch this feature off - would your character be savvy enough to do this?


Unlocking phones
Of course all of this stored data is useless, if you can't access it - and there in lie the challenges and opportunities for writers. Modern phones have screen locks that most people now use. With so much of our lives now conducted through our mobile devices, it's madness NOT to lock your device - if only so your 'friend' can't send rude text messages to your contacts when you leave your phone unattended.
Many devices also encrypt the data held on them, making it theoretically impossible to read the data. As an anti-theft device, many smartphones now have the option to remotely lock and even wipe the data from a phone. For this reason police will often place phones in a 'Faraday bag' which blocks signals to the phone, so the owner can't remotely access it. In a pinch, the shielding on a microwave oven will also do this.

So how does your investigator unlock the device?
PIN Codes
The easiest to use. Perhaps they use the same PIN for multiple devices? Dirty fingerprints on the screen might give an indication of which digits were used, but the possible combinations will soon become unmanageable. Perhaps keep it simple and have somebody look over their shoulder and memorise the PIN as they type it.

Swipe Access
The user swipes their finger across the screen in a pre-determined pattern. Again, grubby fingers may leave a trace on the screen.

Biometrics
Fingerprints, facial recognition, voice recognition - all of these are potential ways to lock a device. The most poorly understood one is fingerprint. You cannot unlock a phone using the owner's severed finger. Nor can you use the finger of a corpse. All modern fingerprint readers use the miniscule electrical charges generated by living cells to generate an image. After death, these charges dissipate. Exactly how long after death this occurs is the subject of some debate - it's difficult to get ethical approval to perform the necessary experiments!
Suffice to say that if you want to unlock the phone of a dead person in your book, they need to be really fresh!


That's all I am going to say about mobile phones for the time being, but there is much else consider. In a later post, I will return to the topic of Social Media, which these days is often linked to mobile devices.

Next week, I will move away from technology for a week and focus on character voice.

As always, if you want to comment on any of this, please do, either here or on social media.


All the best,
Paul