The first three images were taken from the crime scene video. The images show Italian forensic police expert Patrizia Stefanoni collecting a blood sample from the wall in the murder room.
In the first image, Patrizia is swabbing the wall. In the second image, you will see Patrizia turn the swab around. If you look at the swab, you will see the blood sample that was collected from the wall. The swab is turned around and the sample is now facing outward. In the third image, you can clearly see Patrizia's thumb pressed up against the area of the swab that had the blood sample on it.
Patrizia is taking the sample on both sides of the swab. The problem is, she is also getting blood all over that glove. This wouldn't be a problem if she changed her gloves between samples. She simply does not do that. She collects many samples wearing the same gloves.
The two photographs below show a pair of gloves that were discarded on the floor. Look at the mess they made of the cottage on November 3, 2007. Keep in mind, they trashed the cottage in November, then they came back on December 18, 2007 and tested the cottage using luminol. The cottage was completely contaminated long before they did the luminol tests.
Look at how dirty those gloves are. Even more disturbing, the investigator that used the gloves just threw them on the floor instead of properly disposing of them. This is the same floor that would be later tested using luminol.
This section will show how sloppy evidence collection procedures lead to unreliable results.
Contamination on Gloves and Improper Use of Collection Swabs (this page)
Contamination on Gloves and Improper Use of Collection Swabs
Gioia Brocci, photographic agent of the Questura of Perugia, collected the evidence samples in the bathroom that was shared by Amanda and Meredith. Three of the samples showed Amanda's DNA mixed with Meredith's blood. The prosecution has tried to insinuate that these findings are incriminating.
Meredith's blood was visible in several areas in the bathroom. I believe that Rudy Guede used the bathroom to quickly clean himself up. When he did this he left behind small amounts of Meredith's blood. As stated above, three of these samples were mixed with Amanda's DNA. This is completely understandable because the bathroom was used daily by Amanda.
To put this in perspective, think about your own bathroom. Swabbing your bathroom sink in the bathroom that you use daily would unquestionably yield your DNA. When Gioia Brocci collected the samples from the bathroom she swabbed large surface areas to clean up the blood. When doing this she also wiped up Amanda's DNA in the process. When collecting samples, Brocci actually advanced the mixing process. She used the swabs like a cleaning rag.
It was unknown at the time but the drop of blood on the faucet belonged to Amanda. This blood was not mixed with any other DNA. The small amount of blood on the faucet most likely came from an irritated ear piercing. Brocci collected this sample before she collected the other samples on the sink, toilet, wall and bidet.
The video below shows the samples being collected in the bathroom. When watching the video look for these important details.
1. Brocci wiped Amanda's drop of blood off of the faucet before she collected the other samples on the sink, toilet, wall and bidet. Watch her thumb. Brocci kept her thumb down and rubbed her thumb repeatedly over the sample.
2. Brocci did not change her gloves after she collected each sample. (see photos below) Watch as she collected the next sample after the faucet. Once again, she put the same thumb down into the sample that she was collecting. Keep in mind, it was unknown at the time, but the sample from the faucet contained Amanda's blood. She had now repeatedly rubbed her thumb in Amanda's blood and then onto the next sample.
3. When Brocci collected the samples from the sink and the bidet, she used a wiping motion and wiped multiple surfaces with the same swab. She was collecting Amanda's DNA from Amanda's own bathroom as she was collecting Meredith's blood samples. Not only was she collecting Amanda's residual DNA, she was mixing it together with Meredith's blood.
Sloppy Evidence Collection in the Bathroom
After watching the video you can clearly see that the mixed DNA that was collected from the bathroom is not incriminating in any way. The DNA samples can be used to show that Meredith's blood was present in the bathroom. The evidence can also be used to show who possibly used the bathroom. The fact that these samples are mixed, means nothing.
Brocci advanced the mixing process with her evidence collection procedures. She wiped large surfaces when she collected the samples. She did not change gloves after collecting Amanda's blood off of the faucet or after collecting any of the other samples. Both of these procedures undoubtedly mixed the DNA.
The images below were taken from the video that you just watched. The crime scene videos are very choppy. The video is stopped between each sample presumably so Brocci can put the swabs into evidence containers.
Look at the images of the gloves below. Look at the glove on Brocci's right hand. There is a fold in that glove that runs across the back of her hand. In the last 3 images, notice the area of the glove that is rolled up at her wrist. The glove is rolled the same way in all 3 images. One area dips down from the rolled section.
It would have been impossible for Brocci to change gloves between each sample. There is no way that each time she put a new glove on her right hand that the glove would fold the same way across her hand and also roll the same way at her wrist.
We don't believe that Brocci ever changed her gloves when she collected evidence in the cottage. She certainly did not change them when she collected the samples from the bathroom.
In the image below, Brocci wipes Amanda's blood off of the faucet. In all of the images below, you can clearly see the same fold going across the back of Brocci's hand.
In the image below, Brocci wipes Amanda's blood off of the sink. Note that her thumb is down below the swab making contact with the surface of the sink. That is the same thumb that had just made repeated contact with Amanda's blood on the faucet.
In the image below, Brocci wipes a blood sample off of the wall. Note how the glove is rolled at the wrist. You will see that the glove is rolled the same way in the each of the photos below.
In the image below, Brocci collects a sample from the toilet. The hand is facing the other direction but notice that the glove is rolled at the wrist just like the glove in the image above.
In the image below, Brocci collects a sample from the bidet .
To avoid contamination of evidence that may contain DNA, the US Department of Justice, lists the following precautions:
Wear gloves. Change them often.
Use disposable instruments or clean them thoroughly before and after handling each sample.
Avoid touching the area where you believe DNA may exist.
Avoid talking, sneezing, and coughing over evidence.
Avoid touching your face, nose, and mouth when collecting and packaging evidence.
Air-dry evidence thoroughly before packaging.
Put evidence into new paper bags or envelopes, not into plastic bags. Do not use staples.
There is no indication that Brocci ever changed her gloves at the crime scene. In a number of samples, she used a single swab to take material from multiple points on a surface.
The DNA samples taken from the bathroom can be used to show that Meredith's blood was present in the bathroom. The fact that Meredith's blood is mixed with Amanda's DNA is not incriminating in any way.
Click the links below to read more about improper collection procedures.
Substrate Control Tests
Given the significance the prosecution has attributed to these mixed DNA samples, it is unfortunate that investigators did not bother to perform substrate control tests as described in the video below.
a website detailing the wrongful conviction of Amanda Knox & Raffaele Sollecito
Sloppy Evidence Collection Procedures and Contamination