Would the phone apps stop updating for any other reason? Low battery power? Some other reason? Flight mode?
Surely the mum's quote is talking about a different type of communication with the mast? The phone pings regardless of whether or not apps are updating at the time, but it's a different type of ping. If there's no app updating then there's still comm pings that basically say "hi, where are you?"
I don't know how frequent these pings are? If a phone is traveling by car, then won't the distance between pings refer to greater distances than if the phone is traveling at walking pace? More phone masts will add greater accuracy to this kind of triangulation, and more pings+more masts means even greater accuracy even when traveling at speed.
FTR triangulation takes two masts, not three. The third point in triangulation is the object you're trying to find the position of. It's a common error, and I don't think it is relevant, it's just a bugbear of mine, and if someone wants to know for the future, then triangulation requires two spots in addition to the position of the object that you're trying to find the location of. TV shows almost always get this wrong and put up an image of a triangle on the screen with the object in the centre, but that's not correct.
The other thing is that if there's only one mast within distance, then you can't triangulate, you can only give a circle of radius from the mast. I remember when the Malaysian plane (MH240?) went missing that they used ping times to and from satellite(s) to get a distance result, but if you don't have two masts then that isn't directional but would provide inner and outer boundaries for a circle. (I hope that comes over as English and not gobbledegook.) They probably do have more than one mast and are triangulating, but it's the sort of nuance they probably wouldn't communicate accurately to the public. They're not intending to give us the information to run an investigation by ourselves, they're trying to give us the information to determine if we might have seen him that night or if he might be in our garden shed and we should search such an area.
Yet another thing is that when I tried to search the difference between 'off' and 'no battery' it was very hard to get a hard and fast answer. Some people believe some phones will still ping even in 'off mode'. Others say 'off means off'. The only certain thing I could find is that battery out definitely means no ping, but there was so much confusion over what does 'off' mean with mobile phones even amongst people who are tech-oriented.
Mildenhall is in the Barton Mills area, and if you were entering a mobile phone restriction zone, then you might turn your phone to 'an' off position, but how 'off' do you need to be? I would have said no pings off, but for that it should be sufficient to turn the phone to a hard 'off' as you do in a hospital or similar place...no one takes their battery out when they enter a hospital or other computer zone, but they have to turn it off to remove the interference, which I always thought came from the pings? But I could be wrong on that last point as it was just an assumption. I remember an old phone that would send interference through my computer every now and then, but it wasn't more than about every 20 minutes?
I do agree with whoever said about a different ping if the phone is turned off (or on) ... not a different ping per se, but it will have a different message attached to the ping, and it's logical that a sign on/sign off ping might be 'forced' at a different timing interval than other regular comm pings (more gobbledegook, right?)
The quote "hours after" is misleading !
The police say (in an interview after a question from a journalist)
"it was stationary in Barton Mills from when it arrived (4.30am) until 8.00am)
Corrie's mum says (on a tv interview)
"the apps (auto updates) stopped updating (that's how it is traced) when the phone arrived (so, at 4.30am).
You choose !