I want to raise a point of debate with Forensic Focus members.
When the prosecution expert presents his/her evidence is it a requirement for the defence expert to identify all the flaws in advance with the prosecution expert's work, such that the prosecution expert gets to correct all his/her work mistaes before presenting a clean pair of shoes before the jury as if it was right in the first place?
Isn't it really the case that the defence expert is doing the job for prosecution? The point being, if the defence expert assists in that manner doesn't the defence expert in fact become a quasi-prosecution expert helping to present evidence that assists in convicting the defendant?
Doesn't your point of debate largely depend on whether the defence expert's findings agree with the prosecution expert's findings?
And does it not also largely depend on the kind of mistakes we are talking about, and to what degree they will, when all is said and done, prove or disprove the prosecution's/defence's point of view and/or influence the jury's verdict?
I have to say, however, that in theory the expert witness's role, whether defence or prosecution, is to provide aid to the jury. The game to which you allude (the prosecution && || defence of the case) is played between the solicitors/barristers/lawyers.
Cheers
DarkSYN
Surely such things are dealt with before court.
If I were a defence expert I would expect to be asked to comment on the prosecution report in my own report. My own report would be made available to the prosecution counsel and their expert once completed, allowing them the same opportunity to question my findings.
A judge and/or jury may find it a little misleading if you withold things until the day of court.
Doesn't your point of debate largely depend on whether the defence expert's findings agree with the prosecution expert's findings?
How can the findings be agreed if they haven't done the checks in the first place before testing and reporting in the first place?
Surely such things are dealt with before court.
Regrettably we all hoped for that but not so, on numerous occasions.
Moreover, why should the defence expert clean up the prosecution expert's work. That is like asking you to examine my work, clean up my mistakes and I take all the credit for not knowing and get all the money (whilst you give me free training session). At that rate I could just sit back make any general statements concuring with what the prosecution claims, knowing that you, the defence expert, will do my job for me.
As a practicing defense expert, I can give you some insight into what happens here in the US.
The defense is not required to share anything with the prosecution ahead of time, except in rare cases.
Remember, the weight of proving a case is on the prosecution, not the defense.
I analyze law enforcement forensics all the time and find mistakes in quite a few cases. However, mistakes are not what is going to make a difference in many cases.
What makes a difference is relevance and context.
Understanding the process of how a case works through the judicial system is critical to understanding what how an expert should work a case and what an expert looks for.
It is also important to understand how the prsoecution and defense form their "theory" of a case.
My job is to not only check for mistakes in the analysis, but in other areas as well.
Challenging digital forensics evidence is much more involved than just making sure that the same bits and bytes are found by both sides or looking for mistakes or making sure that MD5 hashs match.
I can guide an attorney through the direct and cross examination processes independent of whether or not mistakes were made by the prosecution's side.
Many times, the prosecution will not ask a question about evidence if it does not support their theory of a case.
But the main thing to remember is that if the prosecution cannot prove their case, the defense does not have to present its case at all.
Part of the answer lies in the rules for court procedure, rather than the law, per se, and these differ from jurisdiction to jurisdiction.
In the US in most jurisdictions both sides have a right to know what witnesses will be called and what evidence will be presented, in advance of the trial. In some cases, a preliminary hearing will be held in which the prosecution is required produce evidence sufficient to lead to an indictment. As noted, before, the defense is not required to do anything unless the burden of proof is met.
Either side may challenge the relevance of particular witnesses but, typically, the defense is not required to reveal its case until the prosecution is finished. In civil as well as criminal cases, there may be pretrial motions and hearings to determine what evidence will be heard by the Court and the defense may wish to put on part of its rebuttal at these hearings but it is not required to do so.