Murder Mystery Part 2

Murder mystery part 2

Blood Analysis

The Kastle-Meyer test is a forensic presumptive blood test, first described in 1903, in which the chemical indicator phenolphthalein is used. It relies on the peroxidase-like activity of hemoglobin in blood to catalyze the oxidation of phenolphthalin (the colorless reduced form of phenolphthalein) into phenolphthalein, which is visible as a bright pink color.
A presumed blood sample is first collected with a swab. A drop of phenolphthalin reagent is added to the sample, and after a few seconds, a drop of hydrogen peroxide is applied to the swab. If the swab turns pink rapidly, it is said to test presumptive positive for blood. Waiting for periods over 30 seconds will result in most swabs turning pink naturally as they oxidize on their own in the air.
Optionally, the swab can first be treated with a drop of ethanol in order to lyse the cells present and gain increased sensitivity and specificity. This test is nondestructive to the sample, which can be kept and used in further tests at the lab; however, few labs would use the swab used for the Kastle-Meyer test in any further testing, opting instead to use a fresh swab of the original stain.

Immunoassay Results

Immunoassay is one method of determining the presence of biochemicals in a chemical mixture or biological sample. This technique identifies chemicals by unique features of the chemical’s shape and surface charges. The assay uses antibodies to detect the presence of compounds in a sample. The chemical’s presence is known when it bonds to an antibody and forms a detectable clump known as a precipitation band. Blood typing is one of the earliest forms of immunoassay

Reference Blood Types

‍Crime Scene Blood Types

Blood spatter evidence: TRAIL TO THE GATE

1. 2.

3.

Blood found on cage

Footprint evidence:

Footprint found at crime scene

In answering each of the following questions please provide supporting evidence from the crime information and images provided.

1. Compile a list of evidence that the suspect(s) left at the scene.
2. How do the parents feel about Logan?
3. What was the cause of Marilyn’s contention with Lynn?
4. Was any weapon found?
5. Was the wound in the front or back of Lynn?
6. What type of weapon could have made the wound?
7. Describe the fibers (from clothing) found at scene.
8. Where was the rabbit found?
9. Why did Lynn have blood on her hands and arms but no wounds there?
10. Which of the suspect(s) could have been the likely source of the fibers?Explain citing evidence
11. Is there a history of abuse within the immediate family? Why is it important to know this information?

12. Does any of the suspects have wounds? Logan Olsen has a scratch on his abdomen, no other suspects had wounds
13. Did Lynn and her brother ever have a good relationship?
14. Was the gate to the fence around the property locked?
15. What blood type(s) was/were identified after testing the blood?
16. What blood type is the victim?
17. Why is there different blood to the gate and on the gate?
18. How did blood different from Lynn's get on the cage?

1. Which two suspects could the blood on the cage come from?
2. Is any of the two suspects a more likely candidate? explain
3. Based on the results of the blood evidence, which suspects can be eliminated?

22. Which suspect’s footprint most closely match the footprint found at the scene?

23. Which suspect is the likely source of the hair found at the crime scene?

24. Does the hair on Logan’s shirt belong to the victim?

25. Could there possibly be more than one person involved in the murder of Lynn?

26. Based on the new evidence that have been introduced (blood and footprint), can you identify the

murderer(s) without a shadow of a doubt? Provide support from the evidence reviewed.

27. Reconstruct how the crime unfolded base on your review of the evidence.