Complete the rest of this sheet using research (not wikipedia- unless it’s the only thing not blocked for a topic)

Question

Research the history of using this method as a presumptive blood test, by investigating the role of each of these scientists:

Scientist
Describe this scientist’s role and the timeframe they used this method.
a. Louis-Jacques Thenard

b. Christian Freidrich Schonbein

c. Dr. Kastle

d. Dr. Meyer

Answer 1

Certainly! Below is a summary of each scientist's contributions to the history of presumptive blood tests, along with the timeframes in which these developments took place.

a. Louis-Jacques Thenard

Role: Louis-Jacques Thenard was a French chemist known for his discovery of hydrogen peroxide in 1818. He developed a method to detect blood based on the oxidation of a chromogen in the presence of hydrogen peroxide.

Timeframe: Thenard's work occurred primarily in the early 19th century, with the key discovery in 1818. His research laid the groundwork for later forensic tests for blood, particularly in demonstrating how certain chemical reactions could indicate the presence of hemoglobin.

b. Christian Friedrich Schönbein

Role: Christian Friedrich Schönbein was a German chemist who is credited with discovering the blood test involving the use of hydrogen peroxide as a presumptive test for blood. He demonstrated that hydrogen peroxide could react with hemoglobin to produce a color change, indicating the presence of blood.

Timeframe: His work was significant in the mid-19th century, particularly around the 1830s and 1840s. Schönbein's experiments helped to further the understanding of chemical indicators in forensic science, emphasizing the association between hemoglobin and oxidative reactions.

c. Dr. Kastle

Role: Dr. Castle was instrumental in formalizing a presumptive blood test known for its reliability and effectiveness. He developed a test that utilized phenolphthalein, which turns pink in the presence of hemoglobin, thus indicating blood.

Timeframe: His contributions came to the forefront in the late 19th century, specifically in the 1900s. Dr. Kastle’s test became widely used in forensic investigations due to its specificity and sensitivity to blood.

d. Dr. Meyer

Role: Dr. Meyer, in conjunction with Dr. Kastle, further advanced the presumptive blood tests. He contributed to refining the techniques and methodologies surrounding the testing for blood, with a focus on increasing accuracy and reliability in forensic applications.

Timeframe: Meyer’s work also occurred in the early 20th century, building upon the findings of Kastle and others, around the 1920s and 1930s. His collaborations proved fundamental in developing standardized procedures in forensic testing for blood.

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This overview provides insights into the pivotal roles these scientists played in developing presumptive blood tests, which are crucial for forensic investigations.

Answer 2

Research how to distinguish dog blood from human blood.



Research each of the following cases. Explain the role of blood analysis in helping to solve the crime.
a. Peter Porco case (2006)
What happened in this case:

Examples of blood evidence from the case:

How did blood analysis help solve this case:

b. O.J. Simpson case (1994)
What happened in this case:

Examples of blood evidence from the case:

How did blood analysis help solve this case:

Answer 3

Distinguishing Dog Blood from Human Blood

Distinguishing between dog blood and human blood can be accomplished through a variety of methods:

1. Microscopy: A detailed examination of the blood cells under a microscope can provide insights. Dog blood has differently shaped red blood cells compared to human blood. Canine red blood cells are larger and tend to have a more oval shape, whereas human red blood cells are typically biconcave discs.

2. Blood Protein Testing: The protein composition in dog and human blood is different. Specific antibody tests can detect unique proteins found in each species' blood.

3. DNA Analysis: PCR (Polymerase Chain Reaction) can be used to amplify species-specific DNA from the blood sample. This method is highly accurate as dog and human DNA are significantly different.

4. Enzyme Level Testing: The presence of specific enzymes that vary between species can also be analyzed. For example, the activity levels of certain enzymes may be compared between species to determine the origin of the blood.

5. ELISA (Enzyme-Linked Immunosorbent Assay): This method can be used to detect specific canine proteins and antibodies that are present in dog blood but absent in human blood.

a. Peter Porco Case (2006)

What happened in this case:
In November 2004, Peter Porco was found murdered in his home in Delmar, New York. His wife, Joan, was also attacked but survived. The case remained unsolved for over a year until their son, Chris Porco, emerged as a suspect due to circumstantial evidence.

Examples of blood evidence from the case:

• Blood stains found at the crime scene which matched Peter's blood type.
• Blood evidence on the murder weapon, a hatchet, leading investigators to connect it to the scene.

How did blood analysis help solve this case:
Blood analysis helped establish a timeline and sequence of events surrounding the murder. Blood found on the hatchet linked Chris Porco to the crime. Additionally, the blood pattern analysis contributed to determining how the attacks occurred, ultimately supporting a narrative of premeditated murder, which led to Chris Porco's conviction.

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b. O.J. Simpson Case (1994)

What happened in this case:
In June 1994, Nicole Brown Simpson and Ron Goldman were found murdered outside her home in Los Angeles. O.J. Simpson, Nicole's ex-husband, became the prime suspect. The case garnered extensive media coverage and ultimately resulted in a highly publicized trial.

Examples of blood evidence from the case:

• Blood samples were collected from the crime scene, which contained DNA that matched both Nicole Brown Simpson and Ron Goldman.
• Blood found in Simpson’s white Bronco and on his driveway matched the victims' blood type.
• Forensic analysis also identified blood drops leading from the scene of the murder to Simpson's home.

How did blood analysis help solve this case:
Blood analyses provided crucial DNA evidence linking O.J. Simpson to the murders. The forensic evidence indicated a connection between him and the crime scene, which played a significant role in the prosecution's case. However, the defense questioned the integrity of the evidence and raised concerns about contamination and mishandling, leading to a dramatic trial outcome that ended in Simpson's acquittal. The case highlighted the importance of forensic blood analysis in judicial proceedings, both in terms of supporting the prosecution and raising doubts about the evidence.

In both of these cases, the role of blood analysis was crucial in establishing connections to the victims and suspects, shaping the investigations and subsequent trials significantly.