Types of Fingerprints

Direct: A direct fingerprint is when some kind of substance, ink or dust, for example, gets on your fingers and is imprinted on a clean surface.

Latent: Latent prints are formed when your hands and fingers perspire and form sweat and gets on a surface.

Plastic: A plastic fingerprint is when you put your hands into a material, such as putty, and the material retains the shape of your print.

Analysis of Hair/Fiber Lab

The shaft of a hair is made up of three parts. the cuticle, which is the outside, the cortex, which is the next layer in the hair, and then the medulla, which is the very center of the hair.
We discovered that every type of hair is different. Asian male hair has a spiny cuticle, a black medulla and a dark brown cortex. Black male hair is more curvy and has a brown cortex. White male has a yellowish cortex, a black and smooth cuticle, and a light colored medulla. Dog hair has a crizzled cuticle and lines in the medulla. Then the cat has a crizzled cuticle, a rough and edgy cortex and it was hard to actually see the medulla.

We also had an unknown hair sample that we had to identify using the information we gathered on different types of hair. My guess was the black male hair. The reason is because it had a darkish brown cortex, visible medulla, and a smooth cuticle. So this cancels out the Asian and cat hair, which are both brown.

Comments and Analysis on Blood Lab

In our blood lab, Mr. Kelly had us experiment and find the types of blood, A, B, AB, or O. Though it was not real blood, it had certain substances in it that gave the same effect as blood. We put 2 separate drops of 2-3 drops of blood onto a glass slide. Then we added a blue liquid to one, and a yellow to another and mixed them.
As you can see, in the picture above we tested type A blood. When we added the blue liquid to the left sample of blood, it formed a precipitate. However, when we added the yellow to the other A type sample, it remained clear. It further proves that the blood is Type A. The reason is because for O, the blood is to remain clear when you add the blue and yellow, the A is supposed to form a precipitate from the blue, but not from the yellow, the B is not supposed to form a precipitate from the blue, but is from the yellow, and finally the AB forms precipitates on both when the blue and yellows are added.

Crime Scene Investigation Story

Mike Kelly had been looking around for months trying to find the perfect ring for his fiance, Laurie Smith (made up last name). Mike and Laurie were very happy together, but Laurie did not know she had a stalker. The stalker was a black male, Ralph Johnson. Ralph knew they Mike and Laurie always work late, and planned to sneak into their house to steal the diamond ring to ruin Mike Kelly's proposal. Ralph did not know, however, that Mike came home early to surprise Laurie with the ring. It was rainy and muddy outside so Ralph Johnson came in the unlocked front door and looked around, no one in sight. Surprisingly, he saw the ring box right on the counter. As he was going to go get the ring, he felt something rub on his leg. He jumped and dropped the note he was going to leave behind. It had said, "I have your diamond ring." A cat was running away with the note in its mouth. He knew he couldn't do anything about it. So he just dashed for the ring box, took the ring out and left the box. He also noticed a wallet on a table and went to get it. He thought it was his lucky day because he had found $100 in it. So he took it out and left the wallet there. Then as he was leaving he bumped into a a glass cup. He tried to catch it as it was falling, but he didn't make it in time. He then cut his hand on the glass by accident. Alarmed by how loud the glass was, he quickly out of the house and escaped.

• Footprint was from the rain and mud outside.
• Blood was from glass cutting.
• Fingerprint was from the glass that Ralph broke.
  

Data of Crime Scene Investigation

On our table my group found the following pieces of evidence:

Exh. 1A: Piece of hair
Exh. 2A: Second piece of hair
Exh. 3A: Ripped up note
Exh. 4A: Blood
Exh. 5A: Fingerprint on glass surface
Exh. 6A: Mike Kelly's wallet

We then proceeded to use the techniques we learned to analyze the data. This is what we discovered:

• 1A: Piece of hair: This hair we identified as black male using microscopy.
• 2A: Second piece of hair: We identified this sample as cat hair using the same method as above.
• 3A: Ripped up note: There was some pieces of a ripped up note. Once we put them together, we found out that it said, "I have your diamond ring." We then compared the handwriting to the suspects' handwriting and found that it matched up to Ralph Johnson.
• 4A: Blood: We used a blood typing kit to identify the blood we found. It turned out to be Type A, which suspects' Jenny Cho and Ralph Johnson had.
• 
• 5A: Fingerprint on glass surface: We identified this to be an ulnar loop, which Mike Kelly had.
• 6A: Mike Kelly's Wallet: Had no money, but had an ID.
• 

Crime Scene Investigation

In class, we used forensic techniques we learned to profile a scrime scene investigation. As we walked into our classroom, we were assigned a group letter, and each letter had a different crime scene. I was assigned to group A.

Positive and Negative Blood

Blood is categorized by a letter and either a positive or negative. Blood uses the ABO grouping system for the letter and the Rh factor grouping system for the positive and negative. Positive blood has the Rh antigen present in it's blood plasma, but negative doesn't. People with negative blood can obtain the Rh antigen by receiving it through a tranfusion with another person and people with positive blood can receive blood from people with negative blood because they already have the Rh antigen.

Blood Mixing and Transfusions

Blood mixing and tranfusions has been studied for a long time, but many have led to fatal accidents. The reason is because mixing blood can cause blood clumping or agglutination. Karl Landsteiner discovered that blood clumping was a result of the antibodies of the blood tranfusion receiver was fighting against donar blood cells. Since then, blood mixing and tranfusions have become much safer.

Here is a chart of all the possible blood transfusions:

Major Types of Blood

There are 4 types of blood. Blood types A, B, AB and O. Your blood type is inherited from your parents and is determined when you are born.

Blood Type A: "A antigens on the surface of your red blood cells and B antibodies in your blood plasma."

Blood Type B: "B antigens on the surface of your red blood cells and A antibodies in your blood plasma."

Blood Type AB: "Both A and B antigens on the surface of your red blood cells and no A or B antibodies in your blood plasma. "

Blood Type O: "Neither A or B antigens on the surface of your red blood cells, but both A and B antibodies in your blood plasma."

Techniques Used to ID Hair/Fiber

One of the most basic ways to identify hair and fiber is to use microscopy. Microscopy, in this case, is using a microscope to look at individual hair or fiber samples. The reason why microscopy is so commonly used is because of its efficiency. One single hair left by a person at a crime scene can be used to identify what race they are, whether it be white, black, or Asian. Also, fibers can be used to help identify criminals and people at the crime scene. Fibers are certain materials that come from textiles like cotton or wool. Forensic scientists can identify what kind of clothing the criminal or other person involved in a crime were wearing.

History of Hair/Fiber Analysis

Over the years scientists have developed new ways to catch criminals. One way that has been discovered is the use of hair and fiber analysis. In 1899 a forensics scientist, Francois Goron, led to an important discovery. He told the court that the victim of the murderer had dyed his hair before he was murdered. This helped investigators get closer to finding the criminal.

Inaccuracy in Handwriting

Notes handwritten by criminals can be very useful for crime investigators, but they don't always work. Some of the few reasons why the don't work are:

1. Criminals can change their handwriting.
2. Criminals may type their note.
3. The criminal may have forced someone else to write their note.
4. The criminal have have used something else to write with rather than a pen or pencil.