Monthly Archives: February 2013

Kerrian’s Notebook, p. 69 “What happens to the blood?”

Bloody crime scenes are grisly, and sometimes even tough-guy cops have to put their feelings aside in order to process and maintain the chain of evidence. To have even a chance at getting a conviction, the scene needs to be secured so that people (or animals) can’t contaminate the evidence. Photographs (in some departments, videos) are taken before the collection process disturbs anything. The photos can help detectives figure out where the victim was first struck, whether the victim was dragged or bludgeoned or shot, how many victims were involved, the velocity of the strike, etc.

Examples of blood spatter patterns

Next, the area covered with visible blood is measured and scaled (paper rulers are placed next to the area being photographed). Then it is tagged with information that will help the detectives and/or techs figure out the sequence of events during the commission of the crime.

Blood spatter tagging and scaling

The shapes of the droplets – whether there is a tail or they look like an ellipse or a circle, whether small or large – reveals information. TV and movie watchers often hear the phrase ‘blunt force trauma’ as a cause of death. This most likely means that the victim has been struck with a baseball bat or a bottle or a golf club, with medium velocity, so the droplets will be medium sized.


A high velocity hit (from a bullet) will have smaller droplets because the blood is broken into smaller pieces as it leaves the body and is sprayed onto walls or floors.

Weapons that are close to the scene or involved in the crime also need to be processed for blood and prints


After the visual scans of the room for the visible blood, and the initial photography is done, then the other areas of possible bloodstains can be swabbed, the samples bagged and identified (as to placement in the room). Presumptive tests can be conducted at the scene, using the Field Kits that contain chemicals commonly used for this purpose. Presumptive tests can help eliminate stains that are not blood, but the stains cannot positively be identified as blood until taken to the lab for confirmation – a detail that TV crime shows frequently fudge.

Unknown stain luminesces


Luminescence through orange filter













If the officers can’t see any blood in an area where they know a crime has been committed, the detectives and techs might work in teams to process the room. The room is darkened, one officer sprays the walls with a blood search product, while the other marks the spots that luminesce. The lights are turned on and then the room is photographed, then processed/tested. Spraying and tagging is repeated for floors as well.

Floor luminesces


By the way, blood cannot be destroyed with paint. No matter how many coats, no matter what color paint is covering the evidence of the deed, the tests will always reveal that blood has been spattered beneath it. It gets into every crack and crevice. And it just can’t be washed away. Remember the ‘trace evidence rule’? A crook always leaves something behind.


For all you TV murder mystery fans out there: that bright red blood you see on the bed or wall or floor (many hours after a murder has been committed in the episode) is strictly for show. Human blood turns brown or almost black as it dries.


Homicide evidence is kept for years. Bagged, tagged, stored. Photographed and entered into databases as well. If the suspects aren’t caught right away, then the evidence is still there, waiting in storage, to be matched to other evidence that pops up in later crimes.  Sooner or later, murderers trip up and get caught.




*Photos by Patti Phillips, taken at the Sirchie Education and Training facility, Youngsville, North Carolina.




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Kerrian’s Notebook, p. 68 “Are all handcuffs yellow?”

Photo #1

I like to watch cop shows on TV. Some are more realistic than others, but as a rule, if the main characters are likeable enough, they can keep me on the fan list. Sometimes I watch the shows just to point out the flaws in the detectives’ reasoning to my non-cop pals, but Sheila told me that I should send a letter to the writers instead.


Last week, one of the wives in the group asked about the colored handcuffs she saw on one of the shows. She wanted to know if all cuffs were yellow, or just that color for TV.


Answer? It varies. Many departments across the country use two styles of stainless steel or carbon steel handcuffs, without any color at all. While there have been changes through the years, and differences between departments, if colors are used, it’s generally to indicate the level of danger of the person in cuffs. But, officers have also been known to use pink cuffs to intimidate or embarrass a belligerent suspect. Imagine a big, burly gangster wearing pink handcuffs? He’d never hear the end of the ribbing from the other inmates. More than a couple tough guys have settled down when faced with getting pink bracelets clamped on.



Photo #2

This photo shows two different kinds of cuffs. The pair at the top has a short chain in the middle, a type that has fallen out of favor with some police officers because of the danger of being choked with them by a wily suspect. The hinged pair at the bottom of the photo still has some flexibility in the center, but there is less danger of it turning into a weapon. It’s a type popular for use when transporting several prisoners together.




Photo #3

In most arrests that involve an unruly suspect, the officer wants to maintain maximum control of the situation and cuffs the suspect’s hands behind his/her back. Note: in this photo, the hands have been cuffed so that the palms are facing outward, making it more difficult for the suspect to escape or get a choke hold on anyone.



Another type of cuff is the Hiatt Speedcuff, which has a rigid bar between the two cuffs. The bar is covered with black plastic in order to make it easy for the officer to hold the suspect in place during the cuffing/uncuffing process. While some officers like the control they get, others complain that the rigid design makes it tougher to carry around on the job. I’ve never handled them, but a cop pal who lived in the UK, says they are popular there.


Occasionally we see plastic straps being used in the movies to bind somebody’s wrists. If a real cop is using the straps, it is merely a stop gap until they can be switched for steel handcuffs. If a bad guy is using the straps, it’s because they are cheap and easy to buy without raising suspicion. There’s also no key to lose.


*Photos 1-3 by Patti Phillips, taken at the Writers’ Police Academy.

Hiatt Speedcuff photo from Wikipedia







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