Amanda Knox, DNA, and the Italian Courts

25 May

The Perugia, Italy trial of American student Amanda Knox and her Italian ex-boyfriend Raffaele Sollecito is poised to enter its fifth month.


A third suspect, Ivory Coast national Rudy Guede, has already been tried and convicted for his part in this crime. The question now is whether Amanda and Rudy were involved in the murder of Meredith Kercher or not. Many feel that Amanda is the victim of an overzealous, and possibly corrupt, police investigator. Just ask best-selling author Douglas Preston. He and Italian investigative journalists Mario Spezi were nearly charged as a suspects in a famous serial killer case known as The Monster of Florence by the same investigator. In fact, Mr. Spezi was jailed for a time and Doug was asked, not so politely, to leave Italy. All because they were doing research and exploring this famous unsolved case. You can read about their incredible story in their book The Monster of Florence: A True Story.


Now the Amanda Knox trial is entering its “forensics phase” and the prosecution is beginning to lay out its DNA evidence.

Apparently there were nearly 500 traces of genetic material obtained from the apartment Knox and Kercher shared and where the murder occurred. The prosecution pointed out that mixed DNA samples were found on the knife that is believed to be the murder weapon. The DNA samples obtained from the knife were not blood but rather were called “traces of genetic material.” This most likely means that it was some form of what we call “Touch DNA,” DNA left behind by skin cells that result from simply touching an object. Investigators employed Luminol and exposed bloody footprints, which were found to contain mixed DNA also.

DNA material from both of these young women was found throughout the apartment in such places as the bidet, the sink, a box of Q-Tips, a broken window, a purse, and clothing articles. So what does this all mean? Does this mean that Amanda Knox committed the murder? After all her DNA was found at the crime scene and on such incriminating objects as the supposed murder weapon.

It’s not exactly that simple. The important thing to remember is that forensic evidence does not convict anyone. It merely shows a relationship between a person, a place, and/or an object. It is then up to the judge or jury to determine what that relationship means. For example, if fingerprints or blood or DNA is found at the scene of a crime and if the major suspect says he has never been there, then he has a problem. How did his fingerprints, blood, and DNA end up in a place that he swears he had never been. On the other hand, as in this case, what if he or she had a legitimate reason to be there? What if she lived there? That’s the problem with this case and with this forensic evidence. Amanda and Meredith lived together. One would expect to find fingerprints and DNA from both of them all over the apartment that they shared. Even on a kitchen knife that one would assume both had handled before. Granted, some of the locations of the DNA found in the apartment in this case are troublesome, but the fact that the two girls shared this location makes interpreting these findings very difficult.

How many times during the Scott & Laci Peterson case did you hear someone ask “What about DNA?” What about it? What if they found some of Laci’s blood on Scott’s jeans, or on the kitchen sink, or almost anywhere else? Unless this was a great volume of blood, enough to suggest that the person who bled could not have survived such massive blood loss, it would mean little. They lived together. DNA from both would be expected to be all over the house. Prople cut fingers, get scrapes and abrasions, or simply touch objects in their homes and leave behind blood drops and skin cells all the time. Often unknowingly. So the finding of a few drops of Laci’s blood in the house would of little forensic help. Unless a couple of pints were found. That’s a different story.

The Amanda Knox case has already been extremely fascinating, and with the forensic evidence beginning to roll out, its going to get more so. It will be an interesting one to follow and we will see where all of this DNA testing takes us. I just hope that whatever the outcome, Amanda Knox and Raffaele Sollecito do indeed get a fair trial. Here’s a link to an article on the DNA evidence that is being presented at the trial:

Seattle Post-Intelligencer Article


Posted by on May 25, 2009 in DNA, Interesting Cases


5 responses to “Amanda Knox, DNA, and the Italian Courts

  1. Harry Rag

    May 31, 2009 at 6:32 pm

    For anyone who is interested in the facts behind the media spin, and who cares to learn more about the victim of this terrible murder – Meredith Kercher – there is an excellent discussion board

    as well as an interesting blog

    These online resources are not for profit. Anyone can read and/or participate and people from around the world do. They have followed this case since November 2007, and are in no way related to Amanda Knox. Nor are they her friends.


  2. Johnny

    December 12, 2009 at 4:19 pm

    WHO’S DNA WAS FOUND ON THE ROCK THAT WAS THROWN THROUGH THE WINDOW?????????????????????????????????????????????????????????????


  3. harryrag (@harryrag)

    September 15, 2013 at 9:11 am

    The English translation of the Italian Supreme Court report which explains why Amanda Knox and Raffaele Sollecito’s acquittals were annulled can be downloaded from the Perugia Murder File website:



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