{"id":9251,"date":"2021-09-14T07:00:00","date_gmt":"2021-09-14T11:00:00","guid":{"rendered":"https:\/\/vweisfeld.com\/?p=9251"},"modified":"2021-09-13T19:20:15","modified_gmt":"2021-09-13T23:20:15","slug":"what-blood-stains-tell-us","status":"publish","type":"post","link":"https:\/\/vweisfeld.com\/?p=9251","title":{"rendered":"What Blood Stains Tell Us"},"content":{"rendered":"\n<div class=\"wp-block-image\"><figure class=\"alignleft size-full is-resized\"><img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" src=\"https:\/\/i0.wp.com\/vweisfeld.com\/wp-content\/uploads\/2021\/09\/blood.jpg?resize=243%2C336&#038;ssl=1\" alt=\"\" class=\"wp-image-9252\" width=\"243\" height=\"336\"\/><\/figure><\/div>\n\n\n\n<p>Lisa Black, a guest of honor at the recent Killer Nashville conference, is not only the popular author of several crime series, she\u2019s a certified crime scene analyst. She began her talk about blood stains by reminding us that blood accounts for about eight percent of a person\u2019s body weight, about 5-6 liters for men and 4-5 liters for women. In real numbers, this is about 1.2 to 1.5 gallons. A lot to clean up.&nbsp;<\/p>\n\n\n\n<p>If you\u2019re writing about a crime scene and want to fling some blood around, these are the types of blood stains Black noted (here\u2019s a <a href=\"http:\/\/www.forensicsciencesimplified.org\/blood\/principles.html\">good article<\/a> for more detail and some pictures):<\/p>\n\n\n\n<ul class=\"wp-block-list\"><li>Passive stains, or drips. A droplet\u2019s size will depend in part on what kind of surface it dropped onto (absorbent or not) and how far the drop fell.<\/li><li>Transfer stains\u2014that is, swipes or wipes. People (or, conceivably, pets) get blood on themselves and transfer it from the place of origin to another surface\u2014the bloody handprint by the door kind of thing. I once had a housepainter with a long ponytail, which was constantly getting in the newly painted surface. When he\u2019d whip his head around, I got transfer stains on my furniture, woodwork, and everything else!<\/li><li>Projected or impact stains\u2014a bloodstain cause by <em>arterial<\/em> blood may show an up-and-down pattern due to the pumping of the heart; a <em>castoff stain<\/em> comes from swinging a bloody object, possibly the weapon, and can reveal information about the object as well as the number of strikes (the first strike is \u201cfree\u201d\u2014the weapon isn\u2019t bloody yet); <em>splash or drip patterns<\/em> of a liquid dripping into another liquid; and the very fine droplets of <em>high-velocity spatter<\/em>.<\/li><\/ul>\n\n\n\n<p>As blood flies around your crime scene, the tail on the droplet tells investigators which direction it was traveling and, therefore, which direction it came from. Investigators painstakingly recreate in three dimensions the \u201carea of convergence,\u201d using the shapes and tails of all the drops to calculate angles. This may be a little hard to visualize (the best pictures I found appear to be copyrighted), but <a href=\"http:\/\/dyingwords.net\/forensic-bloodstain-pattern-analysis\/\">at this link<\/a>, which is full of useful information, you\u2019ll find an illustration of convergence under the heading \u201cExamination of a bloody crime scene is a slow and methodical procedures.\u201d Amen to that!<\/p>\n\n\n\n<p>If your character doesn\u2019t see any blood, never fear. There are tools to bring it into view. <em>Amido black<\/em> is a general protein stain that makes fingerprints, footprints, and other patterns visible. Anyone familiar with <em>Gone Girl<\/em> came to appreciate the magic of Luminol, which is specific to blood, and especially useful in detecting minute amounts after attempted clean-ups. It works through a reaction with the iron in hemoglobin.<\/p>\n\n\n\n<p>One last tidbit from Black that might come in handy as you write: Bleach destroys DNA. Plus, as Oyinkan Braithwaite began her award-winning novel, <em>My Sister, the Serial Killer<\/em>: \u201cI bet you didn\u2019t know that bleach masks the smell of blood.\u201d<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Lisa Black, a guest of honor at the recent Killer Nashville conference, is not only the popular author of several crime series, she\u2019s a certified crime scene analyst. She began her talk about blood stains by reminding us that blood &hellip; <a href=\"https:\/\/vweisfeld.com\/?p=9251\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"What Blood Stains Tell Us - tips from a crime scene analyst. What your protagonists can learn; what they reveal.\n","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[174,632,29],"tags":[],"class_list":["post-9251","post","type-post","status-publish","format-standard","hentry","category-first-draft-blog","category-police","category-writing"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p2NkiT-2pd","_links":{"self":[{"href":"https:\/\/vweisfeld.com\/index.php?rest_route=\/wp\/v2\/posts\/9251","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vweisfeld.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vweisfeld.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vweisfeld.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/vweisfeld.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=9251"}],"version-history":[{"count":1,"href":"https:\/\/vweisfeld.com\/index.php?rest_route=\/wp\/v2\/posts\/9251\/revisions"}],"predecessor-version":[{"id":9253,"href":"https:\/\/vweisfeld.com\/index.php?rest_route=\/wp\/v2\/posts\/9251\/revisions\/9253"}],"wp:attachment":[{"href":"https:\/\/vweisfeld.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=9251"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vweisfeld.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=9251"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vweisfeld.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=9251"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}