The first three images below were taken from the crime scene video on November 3, 2007. 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. Unfortunately she does not do that. She collects many samples wearing the same gloves. This certainly leads to contamination on gloves.
The next 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.