What this telemetry stuff tells us, and the police , and soon , a jury, is that Borce, as usual, had no clue as to what he needed to do electronically, technically, morally, fiscally, socially, parentally, husbandly, brotherly, intellectually, and humanely.
Not the faintest idea. He was glooping around dithering from one crises to the other, forgetting phones, remembering phones, trying to figure out where a certain phone should be, at a certain time and losing all track of where it actually was at a certain time.
This kind of thing has tripped up killers far smarter than poor deficient Borce, it was a very hard task he had to figure out, projecting an artifact at one location when it was merrily tootling along a whole other track, where time and space collide.. there are only 24 hours in a murderers day, same as the rest of us, the sun rises and sets the same time for them as it does for us. Nothing is suspended for murder. The points of the compass don't move for murderers... north , south, is always north and south, same as east and west.
Just because Borce needed Karens phone to locate itself at a point he hadn't quite decided upon, doesn't mean the darn phone didn't locate itself anyways....it is the tyranny of technology..
It's like the burial site. Whoever buried Karen was on a time continuum, they had to be back at a certain time, from wherever they left from. They were not on a western journey to , say, the Nullabor plain, continuing on the Perth. They were on an out and back trajectory, unless the murderer lived at Macedon , went to Avondale, murdered Karen and bought her back to his/her residential location . Since Karen knew nobody there , but DID know people in Avondale, that's the most likely site of (a) her murder and (b) her murderer .