This document discusses a murder case involving 4 suspects. The victim was found dead with blunt force trauma in the bathroom of Suspect 2's home. Blood found at the crime scene was type AB negative. Suspect 1 was found to have type AB positive blood, matching the blood at the scene, so they are identified as the likely killer.

1. Blood Groups and Blood TypingBlood Groups and Blood Typing

2. How is blood type determined?
 Blood type is determined by the presence
or absence of antigens on the surface of
red blood cells as well as the antibodies in
the plasma/fluid.

3. What are antigens?
 a substance, usually protein in nature,
that stimulates the formation of antibodies.
 Antigens are found on the surface of red
blood cells

5. What are antibodies?
 Y-shaped proteins, formed within the
blood, which react with antigens.
 Antibodies are found in the blood plasma

7. ABO System
 A and B are antigen glycoproteins found
on the surface of a person’s red blood
cells
 O indicates no antigen present

8. ABO System
 How many different blood types are there
in the ABO system?
 4 different blood types
 What are they?
 A, B, AB, and O

10. ABO SystemABO System
There are four blood groups: A, B, AB, and O.
Blood group A: If you belong to the blood
group A, you have A antigens on the surface
of your red blood cells and B antibodies in
your blood plasma.
Blood group B: If you belong to the blood
group B, you have B antigens on the
surface of your red blood cells and A
antibodies in your blood plasma.

11. Blood group AB: If you belong to the
blood group AB, you have both A and B
antigens on the surface of your red blood
cells and no A or B antibodies at all in your
blood plasma.
Blood group O: If you belong to the blood
group 0 (null), you have neither A or B
antigens on the surface of your red blood
cells but you have both A and B antibodies
in your blood plasma.
ABO SystemABO System

12. Blood Types

13. What blood type is the “universal
donor” ?
What blood type is the “universal
recipient”?

15. BloodBlood
TypeType
AntigensAntigens AntibodiesAntibodies MayMay
donatedonate
toto
MayMay
receivereceive
fromfrom
AA AA BB A andA and
ABAB
A and OA and O
BB BB AA B andB and
ABAB
B and OB and O
ABAB A and BA and B NoneNone ABAB A, B, ABA, B, AB
and Oand O
OO NoneNone A and BA and B A, B, ABA, B, AB
and Oand O
OO

17. Rh Factor or Rhesus Factor
 Besides the ABO system, a person can be
either…
 Rh positive
 Rh negative
 Most people are…
 Rh positive

18. Rh Factor
 The Rh factor is another antigen found on
the surface of…
 the red blood cells
 it can be a problem if a woman is pregnant
and she is…
 Rh negative
 And the fetus is…
 Rh positive

20. Rh Factor
 Normally a mother and her baby have
separate blood systems
 However, there are times when the
baby’s blood may enter the mother’s
system

22. Rh and Pregnancy
 If the mother is Rh negative and is
exposed to her baby’s Rh positive blood,
the mother’s body produces…
 Antibodies against the baby’s red blood
cells

24. Rh Factor
 This is not normally a problem during a
first pregnancy because…
 Antibodies haven’t had time to build up
 During subsequent pregnancies, the
mother is given a drug to suppress her
reaction to the baby’s Rh factor

25. TransfusionsTransfusions
 Blood transfusion is the process of
transferring blood or blood-based products
from one person into the circulatory
system of another.

26.  Mixing blood from two individuals can lead to
blood clumping and even death. This occurs
when the blood of the donor and the blood of
the recipient are not compatible.

27.  When we receive blood that does not
match our own, our body produces an
immune response. This immune response
is similar to one produced when our cells
encounter a pathogen.
 When a pathogen, with unknown antigens,
invades our body an immune response is
stimulated. Antibodies attach to the
unknown antigens and deliver the
pathogen to macrophages which destroy
the pathogen.
www.youtube.com/watch?v=lrYlZJiuf18&feature=relatedwww.youtube.com/watch?v=lrYlZJiuf18&feature=related

29. How is blood typing done?
 Is used to determine the blood groups of
an individual
 Involves mixing the blood with three
different reagents that have…
 A antibodies
 B antibodies
 Rh antibodies

30. Blood Typing
 Agglutination or clumping indicates that
the blood has reacted with the antibody
reagent.
 For example, blood type A will clump
when placed in antibody A reagent.
 Another example: blood type O-
will not
clump in any reagent, since it has no
antigens.

31. O Negative Blood= Universal
Donor

32. AB Positive= universal recipient

33. O Positive Blood=the most
common type

34. A Positive Blood

35. B Positive Blood

39. Recap:Recap:
 ABO and Rh SystemsABO and Rh Systems
 Blood type determined by antigensBlood type determined by antigens
located on red blood cells and antibodieslocated on red blood cells and antibodies
located in the plasmalocated in the plasma
 Four blood types: A, B, AB and OFour blood types: A, B, AB and O
 Rh positive or negativeRh positive or negative
 Transfusion – immuneTransfusion – immune
responseresponse

40. Case Number: 5321Case Number: 5321
London Police Department:London Police Department:
Confidential InformationConfidential Information

41. Known InformationKnown Information
T.O.D: approximately 10pm last nightT.O.D: approximately 10pm last night
Location: 500 Richmond St, London OnLocation: 500 Richmond St, London On
Details: Suspect 2 had some friends over after herDetails: Suspect 2 had some friends over after her
basketball game. At 9:45pm the victim said she wasbasketball game. At 9:45pm the victim said she was
leaving to go home. Everyone said goodbye and theleaving to go home. Everyone said goodbye and the
victim preceded upstairs. Suspects 3 and 4 alsovictim preceded upstairs. Suspects 3 and 4 also
went upstairs to get some snacks before returning towent upstairs to get some snacks before returning to
the basement. At 10:15pm Suspect 1 came home,the basement. At 10:15pm Suspect 1 came home,
he is suspect 2’s father, and found the victim dead inhe is suspect 2’s father, and found the victim dead in
the bathroom. He immediately called the police andthe bathroom. He immediately called the police and
then went to check on his daughter and her friends.then went to check on his daughter and her friends.
Cause of death: Blunt Force TraumaCause of death: Blunt Force Trauma

42. EvidenceEvidence
• Blood type:Blood type:
Victim’s Blood: O positiveVictim’s Blood: O positive
Blood found at the crime scene: AB negativeBlood found at the crime scene: AB negative
• Hair:Hair:
Victim’sVictim’s
UnidentifiedUnidentified
• Murder weapon:Murder weapon:
Candle StickCandle Stick

43. The victimThe victim
AgeAge:: 16 years16 years
Sex:Sex: FemaleFemale
D.O.B:D.O.B: DecemberDecember
26, 199126, 1991
Occupation:Occupation:
StudentStudent

44. The SuspectsThe Suspects
SUSPECT 1SUSPECT 1
AgeAge: 52 years: 52 years
Sex:Sex: MaleMale
D.O.B:D.O.B: October 12,October 12,
19561956
Occupation:Occupation: LawyerLawyer
Relation to victim:Relation to victim:
Found the victim.Found the victim.
Victim was hisVictim was his
daughter’s frienddaughter’s friend

45. The SuspectsThe Suspects
SUSPECT 2SUSPECT 2
AgeAge: 17 years: 17 years
Sex:Sex: FemaleFemale
D.O.B:D.O.B: April 3, 1991April 3, 1991
Occupation:Occupation: StudentStudent
Relation to victim:Relation to victim:
Plays on herPlays on her
basketball team andbasketball team and
has been going tohas been going to
school with the victimschool with the victim
since elementarysince elementary
schoolschool

46. The SuspectsThe Suspects
SUSPECT 3SUSPECT 3
AgeAge: 16: 16
Sex:Sex: FemaleFemale
D.O.B:D.O.B: February 28,February 28,
19921992
Occupation:Occupation: StudentStudent
Relation to victim:Relation to victim:
Goes to school withGoes to school with
the victim. Victim isthe victim. Victim is
now dating her oldnow dating her old
boyfriendboyfriend

47. The SuspectsThe Suspects
SUSPECT 4SUSPECT 4
AgeAge: 17 years: 17 years
Sex:Sex: MaleMale
D.O.B:D.O.B: July 16, 1991July 16, 1991
Occupation:Occupation: studentstudent
Relation to victim:Relation to victim:
BoyfriendBoyfriend

48. Your JobYour Job
Using what you’ve learned, how would youUsing what you’ve learned, how would you
go aboutgo about ruling outruling out suspects?suspects?
 Blood type each of the suspectsBlood type each of the suspects

49. From the Lab…From the Lab…
 Suspect 1’s blood clots in the presence ofSuspect 1’s blood clots in the presence of
A, B, and Rh antibodiesA, B, and Rh antibodies
 Suspect 2’s blood clots in the presence ofSuspect 2’s blood clots in the presence of
B antibodies onlyB antibodies only
 Suspect 3’s blood clots in the presence ofSuspect 3’s blood clots in the presence of
Rh antibodies only.Rh antibodies only.
 Suspect 4’s blood clots in the presence ofSuspect 4’s blood clots in the presence of
B and Rh antibodiesB and Rh antibodies

50. Who did it?Who did it?
 Suspect 1 – AB PositiveSuspect 1 – AB Positive
 Suspect 2 – B negativeSuspect 2 – B negative
 Suspect 3 – O PositiveSuspect 3 – O Positive
 Suspect 4 – B positiveSuspect 4 – B positive
Blood found at the scene was AB negative –Blood found at the scene was AB negative –
suspect 1 is likely the killer.suspect 1 is likely the killer.