Mixed DNA

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In her email home Amanda Knox describes her discovery of the blood in the bathroom:

it was after i stepped
out of the shower and onto the mat that i noticed the blood in the
bathroom. it was on the mat i was using to dry my feet and there were
drops of blood in the sink. at first i thought the blood might have
come from my ears which i had pierced extrensively not too long ago,
but then immediately i know it wasnt mine becaus the stains on the mat
were too big for just droplets form my ear, and when i touched the
blood in the sink it was caked on already. there was also blood
smeered on the faucet. again, however, i thought it was strange,
because my roommates and i are very clean and we wouldnt leave blood
int he bathroom, but i assumed that perhaps meredith was having
menstral issues and hadnt cleaned up yet.
The sink with one Knox and two mixed traces
Mixed DNA on the box of cotton swabs, Knox blood on the faucet
The rivulet of dilute blood, mixed DNA


Apart from Guede's bloody footprints, all of the blood evidence outside of Meredith's bedroom was dilute, indicating that it was spread during and after washing. Five traces of Knox DNA mixed with the victim's were found at the crime scene: three in the bathroom (along with a Knox-only bloodstain on the faucet Knox claimed not to recognize), a mixed sample in a Luminol trace in the hall, and in a Luminol trace in Romanelli's room.


  • On the sink

Rep 24: The blood on the faucet Knox claimed not to recognize was found to belong to Knox alone. She testified that there were no blood traces in the bathroom the afternoon before, so while science is unable to timestamp the stain, Knox herself pegged it to the evening of November 1st.

Next to that, a dilute bloodstain on the box of cotton swabs, is Rep 136, containing a Knox/Meredith DNA mixture.

To the left, from the edge of the sink down toward the drain is a second dilute mixed-DNA sample, Rep 137.


  • Around the drain of the bidet across from the sink (Rep 66):
Dilute blood around the drain of the bidet
Knox/Meredith DNA mix in dilute blood


  • Two more mixed traces were revealed during the December 18 investigation when technicians treated the scene with Luminol. One is located in the hall between the women's bedrooms, and the other is in Romanelli's room.
Sites of mixed DNA in victim's blood


Rep 177 - Knox DNA mixed with Meredith's blood in Filomena's room


The mixed DNA is very incriminating because while the argument is commonly advanced that DNA ought to be found in a bathroom, perhaps even mixed with the DNA of others, Knox's DNA was only found in her own blood which was deposited sometime that night (Knox having testified that it was not there the day before), and mixed with samples of Meredith's blood, either visible to the naked eye or revealed with Luminol. It is difficult to entertain the notion that the mixed traces appear as a coincidence of Knox having spit or bled at some other time only in places where Meredith's blood would be dripped following the murder.

Likewise, if shared housing is meant to excuse the mixed trace in Romanelli's room, it logically follows that Romanelli's DNA should be found in her own room, which it wasn't.