Re: How long does it take human blood to dry on clothes outside the body?

Hello Ruby,

Your question can not easily be answered. There are so many variables to 
consider including the temperature and humidity in the room, the volume of 
blood, location of the bloodstains on the clothing, etc.  A paper by 
Yakhno, et.al. 2007 entitled 'Dynamics of Phase Transitions in Drying 
Drops of Human Serum Protein Solutions' show that people with different 
medical conditions affect drying times of blood serum.  Another factor 
would be medications taken by your father.

I'm afraid that I don't have an answer for you and I would be hesitant to 
believe any expert's opinion, especially if they narrowed it down to a 
tight time frame.

Regards,

Dale L. Laux
Forensic Scientist