Interesting. I don't know who broke the story, the Iraqi or British press, but this should have all been kept hush hush by whatever military unit discovered the drone and terrorist so as to not make them change the programming of their drones.
This report is absolutely hilarious to anyone who is familiar with hobby drones. Many of these fascinating little aircraft are equipped with a "Return To Home" feature which will return the drone to the controller if a problem or low battery power should occur. So if an on-board explosive charge is set to detonate upon landing the irony of this unexpected outcome is clear -- and funny.
I think they are using Drones you can buy online. Don't think they know how to change the program. Some of them will follow you.
The drone was programmed to 'kill the unbelievers'. I guess they should have been a bit more specific.