This might partially answer your question
The prelim is not a full test of the evidence and there is some stuff we don't know.
It is now clear from IE's civil complaint that Grusing was prompted to ask if BM might have gone somewhere else (the infamous left turn) by at least 2 data insights
1. Missing mileage
2. Location data suggesting he drove west
This turned out to be inspired because BM admitted the insights were correct.
IMO
@MassGuy and others are correct that BM admitted to this because he thought the truck telematics had revealed it, but it seems it was a mobile device - likely BMs own phone but potentially SMs as well.
But as Grusing is not a cellular/GPS data expert IMO he stuck largely to his knitting in the prelim.
There is one related curiosity here.
Why didn't telematics show the left turn? (If indeed it did not)
In fact the only telematics data we have is what the defence exhibited in the prelim.
I recall discussions with
@sk716 who is big on the telematics that there were 2 points of note.
1. The telematics exhibited is basically logged data. So every time something happens with the truck, hundreds of tiny data points are saved. But this isn't in itself that useful to humans. Generally telematics would be used to provide data that humans can use like journey data, fuel economy, average speed, journey time, trip mileage yada yada yada. Why is there none of that kind of dashboard reporting data?
e.g GPS positioning data seems to only be logged when the truck stops. Was the truck not capable of plotting it's live route? or was it not saved? or did BM banjax it?
2. The telematics exhibited by the defence is presumably a snapshot of some of the evidence that was discovered. What did they leave out?
tldr - what is curious here about the left turn is that presumably BM did not stop, because we have no telematics end point until he arrives at the RTD bus stop
The last telematics event for BMs truck at the Morphew residence is at 3.49am but the phone does not go dark until 4.23am. This suggests to me the phone was not switched off at the Morphew Residence. Or was he sitting in the driveway in the truck messing with the phone?
I'd really love to hear from the telematics and cellular experts as to how these 2 things fit together. Did the phone shake hands with the network when he turned it off at 4.23 and he didn't realise it would do that? Why don't we have telematics of the left turn? Or do we? Where does the timetable suggest he must have been at 4.23?
IE's civil complaint indicated that there are events on SM's phone that we don't know about, so I am guessing we simply don't have a full deck here, and don't know exactly what the prosecution would argue at trial.
