Question

Early one Monday morning, as Mr. Stevens the custodian, walked through the school, he noticed a foot sticking out from under a science lab bench. Mr. Stevens flipped on the light and saw Mel Brown laying under the lab table. Stevens felt for a pulse. Nothing. He noticed blood on Mel's head and hands; there were blood spatters on the floor and a larger pool of blood on the floor under Mel's head. Mr. Sevens dialed 911. The police along with their forensics team arrived shortly before school started. They collected the evidence and took the body to the crime lab. Using DNA evidence forensics determined that there was two blood samples at the crime scene: Mel's and an unidentified sample. The police asked Mr. Stevens for a DNA sample and he immediately gave them one.Some students had told the police that Mel had been arguing the afternoon before with two of his friends: Carl Smith and Gerald Jones. Mel had apparently done their science lab work and the boys had refused to pay him, as previously decided. The police decided to collect DNA samples of Carl and Gerald as well. The results provided some enlightening evidence: one of the three people tested HAD been at the crime scene! Using STR evidence, can you identify the person whose blood was found at the scene?

Answer 1

Yes STR's can be used to identify whose blood was found at the scene because every individual has a unique number of repeats at the specific loci in their DNA that is being examined during STR analysis at the crime lab.

Step-by-step explanation: