Theory:
Blood analysis is very important at crime scenes. One way to determine if a blood sample belongs to a certain individual is through blood typing. Blood typing involves identifying substances called antigens which are present on red blood cell membranes. Although there are many antigens associated with human red blood cells, the ones which are of importance when blood typing include only those of the Rh (Rhesus factor) and ABO blood groups. In addition to having antigens on the surface of red blood cells, blood of certain types also contains antibodies. Without the proper matching of donor and recipient blood, agglutination (clumping) of the red blood cells may result. Antibodies are small Y-shaped molecules that attach to specific antigens. Anti-A antibodies will stick to A antigens and cause the red blood cells to clump together. Anti-B antibodies will have the same clumping effect on B antigens.

Such clumping may block the capillaries causing tissue damage and ultimately leading to death. Type-O blood is called the "Universal Donor" since there are no antigens on its red blood cells. People of type-O blood cannot obtain a blood transfusion from anyone of another blood type, but they can donate blood to any other blood-type. Type-AB is called the "Universal Recipient" since it has no antibodies. It is important to understand that an antigen is something that is foreign to a person's body. An antigen may be a virus, or, as in blood typing, on the surface of un-matching red blood cells.

Theory:
Chemical analysis often plays a vital role in forensic sciences. Many chemicals found at crime scenes have been very important in closing in on suspects. One of the suspects may work at a manufacturing plant where a specific chemical is prominent in the work atmosphere. A small portion of this chemical (most likely in powder form) could be used to pinpoint a suspect. In the real world, this is a very complicated and technical field. For simplicity's sake, we will deal only with salts. Salts are chemicals which are composed of both a non-metallic, negatively-charged ion, and a metallic, positively-charged ion. When salts are heated in a flame, they burn with a distinct colour. This occurs because electrons in the salt absorb energy from the flame. This causes the electrons to become excited and move to an outer energy level. Since this is such an unstable situation, the electrons quickly fall back to their original position. As they do, they release energy in the form of light. Each salt emits a distinctive colour of light.

The following experiment will show you how to differentiate salts using only a flame.

Materials:

• 0.5 g of Copper Chloride
• 0.5 g of Potassium Nitrate
• 0.5 g of Strontium Chloride
• 0.5 g of Sodium Chloride
• Nichrome wire (approx. 6 cm long)
• alcohol burner or Bunsen burner

Procedure:

1. Heat a piece of nichrome wire in the flame of a hot Bunsen burner or alcohol burner until it is red hot.
2. Touch the hot end of the wire in one of the above salts.
3. Place the salt-covered nichrome wire back into the flame and record the colour.

Conclusions:
You should find that the burning salts emitted the following colours:

Now match that salt to a suspect, and you have a clue!

There are three basic fingerprint formations: loops, arches, and whorls.

Loops

Arches

Whorls

In fingerprint analysis you can get precise matching from performing a ridge count. This involves counting the number of ridges from a point called the Tri-radius to the centre point of the print. A Tri-radius is a point where the ridges meet and form a triangle. These are usually found at the edge of the fingerprint, and are only found in loops and whirls. A loop has 1 Tri-radius, a whorl has 2, and an arch has none.

Here is a practice investigation. This is the fingerprint you found at the crime scene.

Here is a list of all the suspects. Which suspect matches the fingerprint you found?

Name:	Tony Lorenzo
Address:	22 A Torbay Rd. St. John's, NF
Height:	174 cm
Date of Birth:	Sept. 7, 1948
Hair Colour:	Brown
Blood Type:	O-
Left Thumb Print:
Previous Convictions:	kidnapping auto theft carrying a concealed firearm gross indecency
Notes:	found with traces of Strontium Chloride in hair/eyebrows

Name:	Jake Roberts
Address:	Mt. Pearl, NF
Height:	149 cm
Date of Birth:	July 14, 1967
Hair Colour:	Brown
Blood Type:	B-
Left Thumb Print:
Previous Convictions:	breaking and entering burglary vandalism manslaughter unpaid parking tickets
Notes:	apprehended with traces of Copper Sulfate under his fingernails and Strontium Chloride under his cuticles

Name:	Sid Jackman
Address:	Unknown
Height:	181 cm
Date of Birth:	June 5, 1966
Hair Colour:	Blond
Blood Type:	AB-
Left Thumb Print:
Previous Convictions:	failure to carry a poopie scooper while walking dog jaywalking shop lifting stealing candy from a baby drug trafficking
Notes:	found with traces of Potassium Nitrate on his shirt

Name:	Martha Blackmore
Address:	24 Whitmore Dr. St. John's, NF
Height:	120 cm
Date of Birth:	Sept. 14, 1955
Hair Colour:	Dark Brown
Blood Type:	B+
Left Thumb Print:
Previous Convictions:	fraud grand larceny disturbance of the peace gross indecency physical assault on a senior citizen
Notes:	trace quantities of Sodium Chloride found on her hands

If you think that Sid Jackman did it, then you're right!

If you are setting up a crime scene, a fingerprint analysis should be done. To leave a fingerprint at the scene, have the "criminal" apply a small amount of petroleum jelly to his or her finger, and then touch an envelope (Remember! This envelope can contain the trace amount of chemical for the Chemical Analysis, and the hair for the Hair Analysis). The petroleum jelly will make the fingerprint show up better. Have the investigators follow the following procedure to uncover the fingerprint.

Procedure:

1. Brush envelope and letter with charcoal and brushes.
2. Analyse the formations of the fingerprints.
3. If you are doing an investigation, match the fingerprints you have recovered to those of the suspects.