And many more people in between.
So how do labs ensure accuracy? How can we assure the jury that the bag of crack we show them at trial is the same bag taken from the defendant on the street? It's all in the paperwork and the system the lab uses to test the evidence.
Here's the steps in my current county:
1) The police officer recovers the evidence.
2) A police officer seals the evidence in an evidence bag, labelling the bag with identifying information about the case so we all know which case it belongs to. The officer also fills out paperwork that goes to the lab asking for tests to be done.
3) A police officer takes the evidence to the lab. Ideally, this is the same officer who recovered the evidence, although it usually isn't.
4) The lab receives the evidence. An evidence receiver is there during business hours and will physically take possession of it. During off hours, the officers lock the evidence in a storage locker where evidence receives take it from the next day. Paperwork is filled out no matter how it comes into the lab.
5) The evidence receivers send the evidence to the storage unit designated for the type of evidence - DNA, guns, drugs, arson, etc.
6) The scientist testing it removes the evidence and begins working on it. Paperwork is filled out each time the item is moved to note what is happening. Every time an item is unsealed, the scientist marks it on the bag and will reseal it.
7) Another analyst reviews all the paperwork and tests before verifying the results.
8) Once testing is complete, the evidence usually remains at the lab in storage until trial.
9) For trial, I have the officer who recovered the evidence remove it from the lab and bring it to me in its sealed condition. Then, I keep it with me for trial.
The news of rogue chemists over the last few years is disturbing. It happens in a few ways. A chemist falsifies their credentials on their resume, gets lazy and doesn't follow the required procedures, or just makes the results up. Every time this happens, it affects the entire system. First, innocent people might be in jail or convicted due to perjured testimony or falsified results. Second, the procedures of the lab are questioned and in many cases the lab is shut down. Third, it affects every case in the future. Defense attorneys will argue, and jurors will wonder, how anyone can possibly trust any test coming from that lab.
You might wonder how it is possible to falsify results when they get reviewed? Well, the review only extends to the paperwork. A second analyst is not performing a second test on the evidence. That would create double the work for things like DNA which already take two months. The reviewing analyst checks the paperwork, verifying the tests were completed correctly and the results are accurate.
It's similar to wrongful convictions. Every one sends shockwaves through the system, disrupting the foundation upon which a solid case should be built. Once fraud like this is discovered, every case in the lab must be reviewed going back years. It is an incredible waste of time, resources, and someone's liberty. For what? A paycheck? Laziness?
Prosecutors must prosecute these offenders to the fullest extent possible - perjury, filing false instruments, fraud. It cannot be tolerated.