You probably know that mobile phones give out a signal that can be used to track down where they (or their owner) is. This is called GPS (Global Positioning System) and is also used in other devices, like SatNavs in cars.

The police have used a court order to make the mobile phone company release the GPS data from the phones belonging to Edward Melton, Anna Grandisson and Emily Grandisson. Click here to access it: GPS data

• You already know what time the train James was on left Exeter St. David’s station
• His murder logically must also have been on the same train

The Google Maps tool has an option to view GPS location. Click here for detailed instructions: Google Maps GPS Instructions

Each group must;

• Use your Google Map from the CCTV task to plot the location of each of the three suspects in the 50 minutes between James leaving the cathedral and getting on the train
• Discuss theories about what this shows
• Email who you think is the prime suspect to sgt.knight@csibroadclyst.co.uk, with the your group number and ‘Prime Suspect’ in the subject line

Each investigator must;

• Update any of your Suspect Logs if you learn something of interest about any of them
• Make a print out of the evidence showing suspects’ locations