Crime Scene Activity - Putting knowledge to the test!

On November 30th and December 1st, 2011, we came into the classroom to discover three crime scenes set up for us to analyze. I was given the third crime scene, which included the following clues:

Clue 1: High heeled shoe indicates a female victim or criminal was present at the scene of the crime. Footprint does not match the heel's print.

Clue 2: Note that says “Someone please help me!". Handwriting is a match to Tyese Jefferson.

Shown here is Tyese's profile, including her handwriting and blood type

Clue 2A: Note that says “You will never find her” indicates a murder/kidnapping and that the victim was female. The handwriting matches Smokey Johnson's.

Clue 3: Fingerprint- Plain whorl pattern, matches Smokey Johnson’s print.

Clue 3A: Fingerprint- Ulnar loop that matches Sandra O’Connor and Tyese Jefferson.

Clue 4: A golden ear-ring, indicates that either the victim or criminal was a female. Indicates that there was a struggle in which the ring was either ripped out or fell off.

Clue 5: A piece of green nylon, possibly ripped from clothing?

Clue 6: A clear liquid with a yellow-ish tint, contained amounts of iodine. Iodine is used to poison people with thyroid problems, which Tyese Jefferson had.

Clue 7: Large footprint-13.5” long, 4.5” wide. Indicates that either victim or criminal was male

Clue 8: A+ blood sample, matches with Tyese Jefferson.. Indicates that there was a struggle.

Clue 9: A hair strand that matches with black female hair, color was dark brown, light brown, and white. Indicates that there was a struggle that caused the hair to be pulled out, also indicates that the grey hairs would belong to someone old-either Tyese Jefferson or Cindy Brown.

Clue 10: A fingerprint left on glass, could not be identified as either a whorl or a loop due to inadequate powder.

What Really Happened:

Smokey Johnson and Tyese Jefferson are ex-lovers. Upon breaking up, Tyese puts a restraining order on Smokey, although presumably they work in the same school (Tyese as a counselor, Smokey as a cafeteria worker). Bitter from the break-up, Smokey begins lacing Tyese's food and drink with iodine, which he knows is poisonous to her, since she has thyroid problems. 

One day, after beginning to feel the effects of the iodine, Tyese decides to head home early from work. Before departing from school, she stops at the cafeteria to get a drink, which contains iodine. She heads home and, without her knowing, Smokey follows. Soon after arriving at her house, Tyese sees Smokey enter through the backyard, where he leaves a footprint in the sand.

Sensing danger, Tyese writes a quick note, which reads "Somebody, please help me!". Smokey enters the house and confronts Tyese. Although it is unknown what happened between the two, it resulted in Tyese running to the door and Smokey chasing her. At one point, Smokey grabs her and manages to rip free her earring and a few strands of her hair. Tyese escapes and continues to run, and at another point she trips, loses her high-heeled shoe, and cuts herself. She leaves behind a smear of her A+ blood.

As she struggles to get up, Smokey approaches. In an attempt to stop his advances, Tyese grabs at Smokey and tries to push him away. She tears a bit of nylon from Smokey's cafeteria uniform and then drops it as she scrambles to the door. She grabs the doorknob (leaving behind a fingerprint) but Smokey soon catches up. He too leaves a fingerprint on the doorknob. 

At this point, Smokey wins the struggle. He finds Tyese's plea for help and tears it up, and then leaves his own: "You will never find her." It is assumed that Smokey hides Tyese's body, in the case of murder, or takes her away, in the case of kidnapping.

Hair and Fiber Analysis Activity

For this activity, we had the chance to observe different hair samples (including dog, cat, Asian, colored, Caucasian, African-American, and synthetic hair).

For example:

Cat Hair


Dog Hair


Colored-Treated Hair


In class, we also got to view different types of fibers, including cotton, silk, and wool.

For example:

Cotton - cotton is very smooth, having come from a plant.


Wool - having come from an animal, wool is lined with tiny ridges.


I thought it was extremely interesting to observe the different types of hair under the microscope; it was clear that they were all different! For example, the color-treated hair was the dyed color until you hit the root, where you could see its original color poking through the dye as new hair grew in. Dog and cat hair was shaggier than the human hairs, if only a little bit. I learned a lot from this lab, because beforehand I didn't think that hair and fiber analysis could be very helpful to a forensic case, but this lab taught me otherwise once I got to see the difference between all the different types of hairs and fibers!

Fingerprint Lifting Activity

For this forensic lab activity, we practiced different techniques for lifting fingerprints. We practiced lifting prints from dark surfaces using white powder, and also lifting prints from light surfaces using dark powder.

To begin, we first rubbed our thumbs on the sides of our noses, where natural body oil can be found. Then we laid down our prints on the table (which has a black surface). Although the prints were hard to see, we could see it enough in order to apply the powder. Applying the powder was the hardest part of this lab; it took me several tries to get the powder to stick to the print without smudging it! In the end I was able to place tape over the print, which lifted the print (able to be seen because of the powder) from the table.



We repeated this process with a dark powder on a slip of white paper. This one was even harder to do than the white powder, since the black powder was chunkier than the white powder!

Poison Analysis Activity

In this activity, we were given six examples of poison. We also were tasked with defining poison, finding common sources, and finding the effects (or traces) of poison on a person.

Research Results

• What is the definition of a poison?
• A substance that causes a harm (injury, sickness, or death) when introduced to a living organism. They can cause harm either rapidly or slowly. 
• What are some common sources of poison?
• Food poisoning
• Medication
• Venom (snakes, scorpions, etc...)
• Sugar (for diabetics)
• Iodine (for people with thyroid problems)
• Common household chemicals (bleach, etc)
• Cyanide
• Certain gases (chloride, etc)
• Pesticides
• What are some signs of a poisoning?
• Dilated pupils
• Discoloration of skin
• Excessive drooling
• Vomiting (if victim is still alive)
• Increased heart/breathing rate
• Hallucinations
• Drowsiness or hyperactivity
• How do forensic scientists deal with poisoning?
• Forensic scientists can use several different chemicals to test for the presence of poisons, including:
• KI to test for lead
• Starch to test for iodine
• Acid to test for chromate
• KSCN to test for iron

Activity Results

Station 1: Metals
When ingested or dissolved into the bloodstream, these metals can be fatal.

	.5 M KSCN	KI	Acid
Test 1	Negative	Positive for Lead	Negative
Test 2	Positive for Iron	Negative	Negative
Test 3	Negative	Negative	Negative

Station 2: Sugars
Can cause great harm when ingested in large amounts to diabetics.

	1	2	3
Benedict Solution	Negative	Negative	Negative

(Since all tests were negative, we suspect a faulty Benedict solution or the sugar samples were too diluted)

Station 3: Ammonia
A common household chemical that can cause unconsciousness and even fatality when combined with bleach.

	Odor	pH > 7	PHTH turns purple/pink
Test 1	Positive	Positive(11)	Positive
Test 2	Negative	Positive (8.5)	Negative
Test 3	Negative	Positive (8.5)	Negative

Station 4: Aspirin
When taken in large amounts, this common medicine can cause much harm.

	pH <7	BTB turns yellow
Test 1	Positive (5)	Negative
Test 2	Positive (6)	Negative
Test 3	Positive (2)	Positive

This common medicine, usually used to cure headaches, can quickly turn to poison.

Station 5: Cyanide
Causes harm to everyone when ingested

	Turns red with FE+3
Test 1	Negative
Test 2	Negative
Test 3	Positive

Station 6: Iodine
Causes harm to people with thyroid problems

	Blue w/ Starch
Test 1	Negative
Test 2	Negative
Test 3	Positive

When iodine is applied to a cut potato, where starch is plentiful, the affected areas of the potato will turn inky blue/black.

Footprint Analysis Activity

For this activity, my group was presented with a tub of wet sand. We mixed the sand around to make it light and airy in the middle - which is the best medium for leaving a footprint - and then, one at a time, we left a print. We specified the weather conditions (such as the last time it rained, the humidity, etc...) and then noted the special characteristics of the print (left or right foot, length, width, etc...)



During this test, my group realized that we were all wearing the same brand of shoes, Converse. This brand of shoe is peculiar because, printed at the bottom of the shoe, is a label stating the shoe brand and the shoe size. If found at a crime scene, this piece of evidence could be a huge give-a-way of the criminal's identity.

1. What was your analysis for each print?
1. The first print that we analyzed was my shoe print. I was wearing Converse, so you could clearly see "CONVERSE, SIZE 7" printed in the sand. My dimensions were about 12 inches long and 4.5 inches wide. The smaller size indicates a female shoe print.
2. The second print we analyzed was Darcell's, who was also wearing Converse that day. Her print clearly stated "CONVERSE, SIZE 6" on the bottom, and just like mine, this would be a huge giveaway in a real crime scene. Her dimensions were around mine, also indicating a female shoe print.
3. The third print we analyzed was Oliver's, who was also wearing Converse, just a different type. His also clearly printed the brand and size on the bottom of his shoe. The only difference was the pattern on the bottom; while me and Darcell's shoe prints were made up of small diamonds, his included a pattern shaped like an eye and a bunch of triangles. The larger dimensions indicated a male foot print.
2. What were some similarities and differences between the different types of shoe prints?
1. We all were wearing the same type of shoe that day - Converse - so we couldn't get a really clear reading of this. By looking at other groups' data, however, we saw that people wear boots or flats had a huge difference in prints. Flat prints were very smooth with a few ridges across the width. Boots were separated into two sections - the toe and the heel. Converse (or regular tennis shoes) were all in one piece and had a complex pattern of triangles, squares, and diamonds.
2. Similarities were that the flats and the Converse were all in one piece, where the boot had been in two. 
3. What are some similarities and differences between male and female shoes?
1. Differences included that male shoes have much larger dimensions than female shoe prints. 
2. Similarities included the pattern on the bottom of the shoe - male and female shoes don't have different patterns (unless the female is wearing high-heels or something like that) so the patterns can be similar or very different, depending on the brand of shoe the person is wearing.

Witness Experiment Activity

For this activity, we had to pretend that we were witnesses in a crime scene. We were instructed to cut out faces from magazines and then further cut the important facial features (eyes, nose, mouth) from each face. After this, we put together a face using the jumbled pieces and let our partner view it for 5 seconds. Our partners then were instructed to reconstruct the face from the jumbled pile.

This activity enabled us to practice the skills required in order to identify a criminal from a quick glance. 

Drug Analysis Activity

For this section of our forensic studies, we analyzed different types of simulated drugs. We tested with two different simulated drugs: cocaine and LSD. We tested by mixing a small amount of the drug with water and then placing a small drop into the Petri dish. We tested the drops with pH paper strips and the LSD and cocaine reagents.

Research Results:

Cocaine:

1. Chemical Name: Benzoylmethylacgoine

 2. Chemical Formula: C₁₇H₂₁NO₄

 3. pH: 4.5

 4. Biochemical Tests: This drug is detectable in hair for up to 90 days (or until all hairs on head at time of use are fallen), which makes it very easily detected for three months after you ingest the drug! The drug is also found in the bloodstream and urine for five days after the drug is taken.

  

LSD:

1. Chemical Name:  Lysergic acid diethylamide

2. Chemical Formula: C₂₀H₂₅N₃O

3. pH: 4

4. Biochemical Tests: LSD can be found in urine for 24 hours and in the bloodstream for as long as 4 days after the drug is taken. Since LSD is unstable and fragile in heat and light, it must be stored in cool temperatures and dark conditions in order to be detected by drug screening procedures.

Here are the results from our experiment:

Drug	pH	Cocaine Reagent	LSD Reagent
1	Orange/Yellow   pH6	green negative	red negative
2	Blue pH10	blue positive	pink negative
3	Orange   pH3	yellow negative	yellow postitive
4	Green/Yellow pH7	blue positive	red negative
5	Yellow pH7	green negative	red negative
6	Orange pH3	yellow negative	yellow postitive