Blood stains can be very useful at crime scenes. Blood cells can be taken from the stains and can be used to identify the blood type of the individual. This can also help distinguish the blood between the victim or criminal.  Knowing the type of blood from the criminal can help narrow down the suspect pool.
RBC are not part of the DNA profiling of a suspect or victim because they lack DNA. Only white blood cells contain DNA.
This lab made me to think of more questions. How likely is it that there will be or will not be white blood cells in the blood left behind at a crime scene? How many different tests are used to identify DNA from blood? Is this similar to the process of identifying DNA from saliva or tissue?
Overall, I enjoyed this lab. It was interesting to learn about the different blood types and which type can be used universally.