CRIME LAB: Myths & Misconceptions

CRIME LAB: Myths & Misconceptions

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CrimelabI entered the crime lab when I was 24 years old from a middle-class background that hardly hinted at the nature of “life on the streets.” I could write a book about my rude awakening to the greater world, but I thought I’d review some of the myths and misconceptions that I brought to the new job.

Bullet Path Acrobatics

In my youth, I assumed that as a bullet passed though an animal or person, it continued on in a straight line in the same direction the gun barrel was pointed. It was an eye-opener to find that’s not always the case.

Hitting any target can upset the artificial stability imparted to a bullet by rifling. If the bullet starts to yaw, it can change direction. My first experience with this came while shooting 200-grain .38 Special bullets through gelatin. I fired a shot, saw the chronograph screen light blink out and felt a dull thud against my foot. In only 51/2 inches of gelatin, the long, slow bullet turned up and to the right 45 degrees, so it had no problem whamming the chronograph screen and bouncing back to the shooting station.

That was a homogenous target, unlike living tissue. We worked an officer-involved shooting where a policeman made an essentially level shot on an armed assailant with a .357 Magnum hollowpoint.
Having expended most of its velocity in the bad guy’s chest, the bullet exited and struck a wall about four feet behind the suspect. The pockmark on the wall was close to seven feet off the floor even though the exit point on the suspect was less than five feet from the floor. If one assumes that bullets always travel in a perfectly straight line, the officer would have been lying under the floorboards shooting up, something that both civilian witnesses and the officers involved said didn’t happen.

I often wish that some pundits making claims about a certain historical shooting in 1963 would take this very common behavior of bullets more seriously.

Crimelab-Projectile

 

Must Remove That Bullet

Having watched so many movies and shows where doctors dig for a bullet in a wounded man and then proudly clang it into a metal pan, I figured the lab would be covered with bullets from the Parkland Hospital emergency room. This was not the case.

Best medical practice is to fix important bodily bits that the bullet damaged. If the bullet is not going anywhere, leave it and worry about the leaks. Needlessly going after the bullet can increase blood loss and complicate recovery.

What about lead poisoning from a retained bullet? The human body has good self-defense processes that isolate a foreign body by covering it with a biological shell. Old bullets removed years after the shooting look like they’d been repeatedly dipped in paraffin. When our lab developed a relatively easy means of screening for blood lead, the Dallas PD arranged for any officer carrying a bullet or pellets to get screened. During my tenure, no one with a bullet onboard ever turned up with enough elevation in blood lead to warrant concern.

Lethality

I quickly learned that “what hits you” gets trumped by “where it hits you” as the major factor in lethality. I did a survey in 1972 of about a decade’s worth of recovered autopsy bullets. I found that .22-caliber and .38-caliber revolver bullets were almost equally represented and made up about 80 percent of the sample. Everything else fell in the remaining 20 percent. Granted, some people died of penetrating gunshot wounds where no bullet was recovered, but the study was still an eye-opener in that there were as many .22s as .38s in the sample.

Any penetrating injury creates leaks and blood loss that, if not stopped by the body’s defense mechanisms or medical intervention, can kill. The number of areas to be treated depends on the path of the injury. At one time I thought the .32 Auto FMJ was pretty high on the lethality scale because we had a run of fatal shootings with that cartridge where the little bullet seemed to have plenty of penetration and the uncanny knack of finding important things and making holes in them. About the same time, a veteran patrol officer related the story of shooting an armed suspect four times in the torso with a .44 Special loaded with roundnose ammo. The bad guy put down his gun, asked the officer not to shoot him anymore and sat in a chair while waiting for the ambulance. He was out of the hospital and in jail in a little over two weeks.

Projectile size is a second-order issue in lethality, subordinate to what organs were hit and how quickly medical treatment was started. A doctor does not need to know the caliber of bullet to save a life.

Bullet Meets Ice

One of the old firearms identification texts showed a picture of a .22-caliber lead bullet that had been recovered using ice. At the time we saw this, all we had was a cotton box and saw entirely too many bullets that were badly scrubbed when we tried recovering in cotton. We were still in temporary digs in a construction trailer in 1971 awaiting completion of a new lab building.

Our first reaction was that ice should destroy a soft lead bullet. However, the picture showed an undeformed bullet. Then after one particularly frustrating afternoon trying to get decent test bullets from a .22 LR revolver, we decided to try ice. We filled a half-gallon paper milk carton with water and stuck it in the freezer. The next morning we had a seven-inch column of ice ready for shooting.

If any of you are responsible for workplace safety, you may wish to jump ahead, because we were definitely not acting responsibly at this point. At least we waited until the other occupants of the trailer were away on coffee break to do the dirty deed. The ice block stood on the floor atop several thick phone books, and we wrapped layers of carpet scraps around and over it. And we pulled the trigger.

We found the frozen milk carton intact with only a few ice shavings spattered on the improvised shielding. The bullet was visible about five inches from the top, and the ice was refrozen around the bullet. We had to thaw the mess to get the bullet, but we were rewarded with a perfect test bullet for the comparison microscope.

The mechanism was clearly that ice melted under pressure, slowing the bullet in the same way water does. It quickly became obvious that this method had cartridge limitations and logistics issues, so when the new lab with its water recovery tank was move-in ready a few months later, we were relieved. So were the nice ladies who shared the old trailer with us.

 

 

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November 29, 2017 at 09:53PM

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