I would think that would be helpful Dave. Any thoughts why forensics gave up no trace of C in the lorry? Or why he was not found at other stages?
I posted my thoughts on forensics somewhere earlier on probably another thread that has since been closed down in order to open a new thread, but in essence the Police in the UK now suffer from a major shortage of detectives - you have detectives working on 20 cases simultaneously, which has lead to lots of them resigning.
In this scenario you end up with a situation where you need fast results, and in simplistic terms, since everyone believes DNA is the be all and end all - if DNA is present = guilty ; if DNA is not present = not guilty.
But as we all know, an absence of evidence is NOT evidence of absense, and with this there still may be more than meets the eye, ironically because of the lack of DNA, but in terms of finding people guilty - especially where Low Copy Number DNA is involved - it needs to be scrapped mucho pronto.
LCN DNA "analyses" DNA fragments that are 1 millionth the size of a grain of salt by "amplifying" it - in other words, as you speak or even breathe you are churning out amounts of DNA that are thousands, tens of thousands, or depending on how long you're in one particular spot maybe millions of times that amount of DNA just through your breath.
If you were to breathe on a table, I touch it, I put my hand in my pocket and take out a coin, it goes in a till and contaminates all of the other coins in there, they are taken by lots of other people all over the country, someone else touches one, then touches a light switch, someone else touches it while wearing gloves, opens a door, goes into a room and kills someone - and your DNA is there, even though you weren't.
It is that easily transferable - which is why a 15 year old boy from Newcastle was the prime suspect in a major IRA bombing in Ireland - even though he'd never left England.
On top of that is that the "amplified" DNA profile is not an accurate representation of the actual DNA, but has to be "interpreted" which involves a subjective interpretation of it, which in other words means it's open to lots of Human error - in other words it has more in line with witchcraft or reading chicken bones than science.
Anyway, off the DNA soapbox, onto the checklist of why the readings from machines should NOT be trusted.
My interest in the bin truck weight was because a) I worked in electronics and the measurement of signals, and b) I used to work with a guy who went on to work for the company who made the load cells for bin trucks - they were called PM on Board, who were eventually bought out by Vishay, and the guy I knew who worked for them - went to prison for fraud.
So, perhaps my initial thoughts were influenced a bit, but from my own knowledge and experience of electronic measurement systems:
1) The system MUST be calibrated ACCURATELY to give a meaningful reading.
2) If it isn't calibrated accurately, then the reading is meaningless.
3) If the calibration has been deliberately altered (eg fraud) then the reading is meaningless.
4) If the calibration has wandered through temperature, vibration (to parts of the circuit), etc - the reading is meaningless.
5) The system has to be working properly.
6) If the system has any kind of fault, then the measurement is meaningless.
7) Even if the system tests okay later, it may have an intermittent fault - a dry joint on a resistor for example, depending on the temperature and exactly when the test is done - could give a positive result (ie working) when it may not have been working at some other time.
8) Even if the load cell (the weight measurement device) is calibrated, and the system at this point is functioning correctly, the recording system / interface could still be faulty and/or not recording accurately.
9) The data has to be taken from the truck to some other permanent recording device.
10) If done electronically it could be incorrect.
11) If done manually it could be recorded incorrectly (by accident).
12) If done manually it could be recorded incorrectly (deliberately).
13) The wrong data for the wrong truck could be given to the Police accidentally.
14) The wrong data for the wrong truck could be given to the Police deliberately.
15) Data from the wrong date could be provided.
16) etc
You have all of the possible system problems, then all of the interface system errors possible, then the human errors possible, all of this just with taking the initial data.
Then you have all of the possible system problems, then all of the interface system errors possible, then the human errors possible, with the recording of the data.
Then you have all of the possible system problems, then all of the interface system errors possible, then the human errors possible, with recovering the data for the Police.
Then you have all of the possible system problems, then all of the interface system errors possible, then the human errors possible, with the transfer/handling of the data by the Police.
And that's just Human error - not including deliberately misleading them with wrong data, truck details, etc, etc, etc.
Multiply it up and it's a nightmare, but the one thing I learned in my time in electronics was - never believe 1 reading, take another and another, and another and test and test and test again.
If what you're seeing is not consistent with the readings - the readings are WRONG.
As in this case.
