People murdered each other in the Middle Ages. How did a medieval detective go about finding the murderer? Many authors have written medieval murder mysteries and if the Brother Cadfael mysteries are anything to go by, medieval forensics were a primitive, but burgeoning science.
Some things that a medieval detective could determine:
Time of death: “Rigor mortis—literally, “death stiffness,” happens very methodically—from the face downward about 2 hours after death. It takes another 8-12 hours for the body to become completely stiff and fixed into position. Fixed for another 18 hours is called the Rigid State. Then it reverses in the same order it appeared for another 12 hours—(Flaccid state). What is rigor? When the blood stops flowing from the heart, the natural bacteria in the body can no longer be fought off and they go to town, creating chemical reactions that prevent the muscles from contracting, which makes the body stiff. Heat quickens the process and cold slows it.
The Greeks and Egyptians had their own system: Warm and not stiff: Not dead more than a couple hours. Warm and stiff: Dead between a couple hours and a half day. Cold and stiff: Dead between a half day and two days. Cold and not stiff: Dead more than two days.
Livor mortis or lividity or post mortem hypostasis (literally “after death state”) is the state of being blue, or colored blue. What is this? Blood stops flowing and pools in the vessels in the lowest point due to gravity. Wherever the body is in contact with, say, a floor, the skin becomes pale ringed by lividity. It shows up 30 minutes to a couple of hours and stays fixed after 8 hours. The detective would know if a body had been moved if lividity had set in on the wrong part of the body.” http://workingstiffs.blogspot.com/2009/09/more-medieval-forensics-part-two.html
Poisons: Thanks to Brother Cadfael, we have many, many medieval poisons, most of which leave some kind of trace. The four most common were Belladonna, Hemlock, Monkshood/Wolfbane, and Foxglove. I discuss their attributes here. Poison was generally considered a ‘woman’s’ weapon, as compared to brute force or bludgeoning anyway which scales 80-20 men to women instead of poison’s 50-50. http://www.npr.org/templates/story/story.php?storyId=125502336
Blood spatter: Certain aspect of medieval forensics involve close observation of the remains. Did the dead man die where he lay? Which way did the blood flow? Was he stabbed in the heart, meaning he knew his victim, or was he killed from behind with a garrote or a blade?
More commonly even then now (and now it is very common), deaths are caused by people who know the victim. In small communities in the Middle Ages, individuals close to the dead person would come under immediate suspicion, and unless the person was killed by an arrow, a murderer would have had to have close contact with the victim in order to kill him.
This article suggests that the murder rate in Europe (Germany in this case) was very high in the Middle Ages, 20-100 per 100,000 as opposed to 1 in a 100,000 now: http://andrewhammel.typepad.com/german_joys/2007/04/german_murder_r.html
“The murder rate was far higher in those days than it is today. It’s hard to know the true homicide rate because reporting wasn’t as accurate in those days and crime-solving was basic and often unreliable. But we do know that violent crime was a far bigger problem in Medieval times than it is now.
For example, the number of murders per 100,000 people in 1995 to 1997 in London was 2.1. But according to one historian, it would have been about 12 murders per 100,000 people in Fourteenth Century England. [The National Archives]” http://lcjb.cjsonline.gov.uk/Cambridgeshire/1534.html