Forensic Question: Testing a Blood Sample for Pregnancy

Jordyn Asks:

Can you test a blood sample to see if the person who left the blood behind is pregnant?

Amryn Says:

For most traditional tests, it would require a fair amount of blood be left behind in order for perform a pregnancy test. The blood would also need to still be in liquid form rather than dried.

It’s not something that would be done for a variety of reasons, not the least of which is that samples are usually conserved as much as possible for forensic testing. So while it’s possible with the right set of circumstances, it likely wouldn’t be done since the blood would be used for DNA testing rather than diagnostic testing.

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Amryn Cross is a full-time forensic scientist and author of romantic suspense and mystery novels. Her first novel, Learning to Die, is available on Amazon. The first book in her latest series, loosely based on an updated Sherlock Holmes, is available for pre-order on Amazon. Look for Warzone in January 2015. You can connect with Amryn via her websiteTwitter and Facebook.

 

How to Determine Blood Type

In the age of DNA testing, blood typing seems to have fallen by the wayside in use in novels but I think it can still be very valuable and add an element of suspense and surprise. A child’s blood type may be the first clue to a parent that they may not be biologically related.

Blood type is determined from two allele’s. An allele is a “form of genetic information that is present in our DNA at a specific location on a specific chromosome”.

There are four blood types: A, B, AB, and O. Blood type A can be designated either by AA or AO. Blood type B can be designated by BB or BO. This will be clearer below.

This is the easiest way I’ve been shown to determine a child’s potential blood type. In the square below, the top horizontal portion is one parent, the vertical side is the other parent. Each box with a single letter is the one allele that parent will give their child. A child receives one allele from each parent so you need to “cross multiply” each square to determine blood type.

A O
O AO OO
O AO OO

In the above instance you have one parent that is blood type A (designated AO) and one that is blood type O (designated OO). As you can see, their child would have a 50% chance of having blood type A and a 50% chance of having blood type O.

Let’s look at another example. Take a look at what happens when both parents are blood type AB.

A B
A AA AB
B AB BB

In this case, their biological child would have a 25% chance of being blood type A, a 50% chance of being blood type AB, and a 25% chance of being blood type B.

How can this work for your fiction? Let’s look at this example. You’re writing a novel that centers around a child diagnosed with leukemia. The child needs a bone marrow transplant. The presumed parents are blood type A (AO) and blood type AB. You have a child with blood type O. Can this child be the biological offspring of these two parents?

A O
A AA AO
B AB BO

Give your answer in the comments section.

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Resources: http://www.biology.arizona.edu/human_bio/problem_sets/blood_types/inherited.html. This resource includes a blood type calculator!

Visit with Colorado Coroner Chris Herndon

Most people imagine Sunday afternoons to be filled with watching sports and hanging with family. But, if you’re a nurse and an author, you think there’s nothing better than to go to a talk given by the local coroner, Chris Herndon.

Chris Herndon

That’s what I did a few Sundays ago (a few years ago!) This information is reposted from September 2, 2011. I’m working to preserve posts that didn’t transfer between Blogger and WordPress. And if you remember the first time this story ran, I owe you my sincere gratitude for being such a faithful blog follower!

As always, I’m always intrigued by medical things and myth busting. Here’s a few highlights that I thought were of particular interest for writers. One even busted a myth I had in Proof. Good thing I was able to change that before the book went to print.

Item One: Do coroners really wear Vicks VapoRub under their nostrils to mask the smell? She says no— going on to explain that this ointment “opens up the nasal passages” and “why would I want to do that?” Much better to work with a bad cold to block out the smell. I will say though that I will often put on a mask or chew gum to help me. Chris mentioned she always has mints on hand.

Item Two:  Six weeks for DNA testing unless done by a private lab.

Item Three: Victims who drown in flood waters are generally found nude as the water will rip off their clothing.

Item Four: Often times in suicide pacts, one person will not follow through.

Item Five: It really does not pay to drink then cut thyself.

Chris shared two stories that exhibited this.

The first was of a man who was drunk and high (double bad combo) and decided to harass an old girlfriend. He punched his hand through a window, cutting the underside of his arm, severing his brachial artery. After this, he staggered through the parking lot until he dropped dead. Upon police arrival, they follow the trail of blood to the broken window and asked this woman why she didn’t call police after he broke it. Sadly, she’d been harassed so often by this gentleman that she’d given up asking the police for assistance.

Second was of a man who was on the blood thinner Coumadin for atrial fibrillation (an irregular heartbeat.) This gentleman decided to cook while drunk. He dropped a knife on the top aspect of his foot and severed the dorsalis pedis artery. He doesn’t realize he’s injured himself as there was evidence that he’d walked to the garage to get paper towels to wipe up the mess. He begins to not feel well, so he sits at his kitchen table and places on a home blood pressure cuff. Loss of blood will cause you to feel weak, lightheaded, and dizzy. This is where he’s found dead. At the kitchen table, sitting up with a blood pressure cuff in place. A pool of blood by the injured foot.

His blood alcohol was over 0.350. That’s a professional drinker….

So people, please, no drinking with sharp implements! Really . . . no drinking in excess would be great for us ER professionals. Moral: Have at least one sober person that you haven’t relentlessly harassed present to call 911 for you.

What other morals do you see? Have you written any of these particulars in your manuscript?

Author Question: Police Officer DNA

Victoria Asks:

I am writing a book and hoping you could help me with a question I have. Would a cop’s DNA come up in the system if it is collected from a rape victim ?

Jordyn Says:

This is a very intriguing question you ask and I actually had to go to my brother (thanks, Karl!) who works in law enforcement as a detective for the answer.

What follows is his take.

When cops are hired their fingerprints are taken. If their DNA was needed to differentiate their DNA from another person’s at a crime scene they would do so, but it’s not a routine thing.

Lots of cops are former military and I would say in the last twenty years if you served then your DNA would be on file somewhere. I don’t think it would be part of CODIS (the Combined DNA Index System) though because that’s only a criminal database.

If a cop was suspected, I’m not sure there would be a backdoor way to get his DNA profile from one of those sources I mentioned (military or CODIS). Officers working the case could easily swab something like his patrol car, computer keyboard, or something else owned by the department because there’s no expectation of privacy there.

In the last ten years or so a lot of jurisdictions are collecting DNA from any person arrested on a felony. The court orders it. I’m sure there have been challenges and as far as I know it has been held up.

Also, anytime there’s a new submission to CODIS, the profile is automatically checked against unsolved crimes. When police take DNA from a crime scene with no suspect, they submit the profile to CODIS and it goes on record. Later, if someone is arrested for a felony and their DNA is submitted to CODIS, now matching a name to the profile, it could clear the older case.

Men Who Kill Women

Regular followers of my blog know that my medical nerdiness can reach into other areas of science like forensics and psychology. I was actually doing a search on women who kill men when I came across this very interesting article on the opposite— men who kill women. Information in this post comes directly from the Vice article entitled Inside the Minds of Men Who Kill Women posted August 10, 2015.

Married couple and criminologists from the University of Manchester, Rebecca and Russell Dobash, spent a decade interviewing men serving life sentences in seven different British prisons. According to the article, this was the largest study done to the date of the posting. They have also published a book on the subject (photo right).

There were some consistent similarities that pertained to these men. “They found that many women are murdered by jealous, possessive, and controlling men.”

Here are some of the highlights.

1. In the majority of cases, men kill out of sexual jealousy. They are possessive. And this possessiveness can also lead these men to kill others close to their victim like her children, family, and friends.

2. Many had problematic childhoods and adulthoods that consisted of alcohol use and unemployment. The authors suggest that the use of alcohol is common to Britain and doesn’t necessarily mean illicit drug use as perhaps is the case in the US. Though they don’t specify this difference.

3. Many are sexual predators.

4. Older women, over the age of sixty-five, are considered vulnerable and therefore worthy targets. Living alone does add risk.

5. The murderers were largely not remorseful of their crimes.

6. Surveillance programs that force violent men (before they murder) to understand denial, remorse, and empathy could prove helpful. Also suggested are developing youth programs to teach people how to handle breakups.

I also highly recommend all women read The Gift of Fear by Gavin de Becker. I think it should be required reading of all girls over the age of fourteen. The sooner they can learn these skills the better.

Escaping Hunted

Hunted was a new reality show that aired earlier this year on CBS. Nine pairs of people “go on the run”. If they survived twenty-eight days they won $250,000 per team. This show was really interesting as an author to watch because it highlighted what kinds of tactics law enforcement uses to capture evaders of justice. Some things I didn’t even know existed.

Here are things NOT to have your characters do if they are on the run from law enforcement.

1. Don’t contact anyone you know. The couples that lasted the longest really stayed away from their network of friends and family.

2. Internet use will be your downfall. The hunters, as they are called, comb through all your social media and even use it against you. In one instance, they saw one contestant loved a particular basketball team because he had photos of being at their games and wearing their jerseys. The team’s name ended up being a password to one of his online accounts. They also would post “wanted” posters on contestant’s Facebook page asking for help in locating “fugitives”.  Also, deleting your social media accounts doesn’t really work. “Nothing is ever erased on social media.”

3. They will access everything to try and find you. They can access real time banking information. Vehicle registration. Closed circuit TV cameras. They’ll look at your old high school yearbooks. There are systems in place on major highways that automatically capture and scan license plates and they can put an alert out for it.

4. Burner phones. Burner phones may not necessarily be the answer. Although the phone may not pop up with a name, they can see the phone number that you’re calling from on the receiving person’s phone bill. A new, unknown number calling? They’re going to guess that it’s you. Once they pin down the phone number, calls between you and people you assume are safe can actually be listened to.

5. Telematics. In all cars built after 2010, GPS satellites can be used to track your car.

6. Mail Cover. Did you know the post office takes photos of every letter sent through their system? Yea, me either. A warrant can be issued for a particular address to try and find you. Here’s an interesting news story specifically about mail cover.

7. Don’t do something you would normally do. If you’re a parent, don’t call your children. If you’re an outdoor expert, maybe don’t go camping. Many duos were successful if they stayed off grid, but many also grew tired of being on the run after a few weeks and would contact friends and/or family for respite. That’s when they were usually caught.

Hunted was a fascinating show of real life cat and mouse. If you’re an author, it’s definitely worth the time in research to take in the episodes.

Only two of the nine couples made it twenty-eight days. Do you think you could last that long?

Child Abuse Injuries: Part 1/2

I read a lot of fiction. Okay, suspense fiction. What I find missing is an area that seems to be in few books yet inherently has a lot of conflict. Child abuse. What fiction titles are you aware of that, as a central theme, center around child abuse?

April is Child Abuse Awareness Month so I thought I’d do a few posts about child abuse injuries and how medical providers pick up on the fact an injury may be intentional or inflicted.

As a pediatric nurse, I’ve been witness to child homicide at the hands of abuse. Yes, it is murder. It’s a necessary part of my job in dealing with these families, perhaps even the confessed abuser, as I care for the child abuse victim. And yes, there is a lot of conflict in these situations.

How do we as pediatric medical providers begin to suspect that an injury is abusive? During the initial evaluation of an injury, confession among abusers is rare (perhaps, they will confess later.) Often, there is a history given to account for the injury. Both parts: the history of the injury and the injury itself can give red flags for child abuse. Today, let’s examine the story and how it may signal an abusive injury.

The story concerning the injury:

1. Is not realistic considering the child’s developmental level. This is more common than you might think. Most people cannot rattle off when a child should meet certain developmental milestones so they’ll say the child injured themselves in a manner that is beyond their developmental age. For instance, “my daughter broke her arm by rolling off the couch”. The baby is two-weeks old. Infants typically roll over starting at 3 months. Here’s a great resource for any writer/parent for developmental milestones.

2. The story changes. Just like other criminals, abusers can have a hard time keeping their story straight. Often times, the more abusers are questioned about the plausibility of the story, it will begin to change. Medical staff interviewing a potential abuser can be like a detective getting a criminal to confess. The doctor will often approach the caregiver several times to ask questions about the injury to see if the story changes. In later interviews, the doctor may say, “This injury is suggestive of abuse.”

3. The story has too much detail. This one may seem odd but it can be a red flag for abusive injuries. If you have children, think back to their toddler/elementary school years when they seem to come home with lots of bumps, bruises, cuts and scrapes. If asked, could you come up with an explanation for each and every injury? Likely, no. Abusers will try and explain away every injury. A non-abusive parent will be truthful and likely say, “I have no idea how that happened.” and then probably feel guilty about not knowing.

What other parts of a medical history/story might give a signal for abusive injury?