Disclaimer: I do not own CSI or the character Gil Grissom. I am not making money off this story, so don't sue me.

Author's note: I wrote this story as part of an assignment for my forensics class. After I turned it in, I started to wonder how it rated not as an assignment, but as a story. Please let me know what you think.

Professor Davidson looked over his five failing students. Each one was in danger of not graduating from University of Nevada due to their terrible marks in Forensics: Catching the Crook. All five were aware of this, and all five stared nervously back at their silent professor.

"I have watched you this semester," he said, finally speaking, "You are all brilliant, there's no denying it. You have the eyes that can see things that others miss, and that is needed in this field. Yet, you're failing, and it's all due to these horrible essays."

The students seemed to shrink inward with each word. They hated disappointing Professor Davidson. He had been their mentor for the last four years, and had encouraged them to in their quest to become Crime Scene Investigators. Now all those late night study sessions, and extra tutoring were going to be for nothing.

"I have talked to the administration," he continued, "and have gotten permission for you five to take a special exam. This exam will decide if you pass or fail my class. It will count towards 75 of your final grade. This is your only chance, pass or fail."

"Professor?"

"Yes, Anna?"

Anna Wint, a young woman with shoulder-length blond hair and bright eyes, looked nervously at Davidson. She carefully asked, "When will the exam take place?"

Davidson was interrupted, as the door to the lecture hall was opened and a tall older man with close-cropped brown hair and graying temples walked in with a stack of papers and a large silver carrying case. "Class," Davidson said, " Meet Gil Grissom. Mr. Grissom, meet my students."

"Class," said Grissom, with a nod.

"As for the exam, Anna, it starts now. Have fun," and with that Davidson strode out.

Before anyone could speak, Grissom walked over to Davidson's desk and set the papers and case down. Turning to the still quiet class, Grissom motioned for them to take their seats. Surveying them, Grissom said, "I will be administering the exams. There will be a different test for each you. During the tests, only the one taking it will be permitted to speak. If anyone else talks, everyone fails. When you are done with your test, leave quietly, and do not enter again until everyone is done. Now, we will start with Anna Wint."

Anna walked slowly to the professor's desk and waited for instructions.

"Miss Wint, your paper over testing for the presence of blood was the worst all your grades. Tell me, how does a person test for blood?"

"Sir," she began, "you can test for blood by spraying an object or area with certain chemicals. Three examples of those chemicals are phenolphthalein, leuco-malachite green, and hydrogen-peroxide. After you have sprayed the object or area you are testing, you watch for a reaction that would indicate the presence of blood. For the three chemicals I already named, phenolphthalein would turn a pink-red color, leuco-malachite green would become a blue/green color, and hydrogen-peroxide would produce bubbles."

"Why would someone test for blood?"

"To find out if an object is the weapon used in an attack or homicide, or if an area is the site where an attack or homicide took place."

When Anna stopped speaking, Grissom opened the case, and took out a kitchen knife, a rock, a baseball, and three vials. "Miss Wint, those three chemicals you named are in these vials. Now, find me the murder weapon."

Anna set to work, and five minutes later reported, "Sir, the weapon was the rock."

"Are you positive?"

"Yes sir. I used a dropper to let three drops of phenolphthalein fall on the rock, and the rock turned pink-red. I used another dropper to let three drops of leuco-malachite green drop onto the rock, and it turned blue/green. And the hydrogen-peroxide produced no bubbles when I used another dropper to let three drops fall onto the knife and baseball."

"Why only the hydrogen-peroxide?"

"The knife and baseball could have been cleaned with household chemicals, and household chemicals produce the same kind of reaction as blood when they come into contact with leuco-malachite green and phenolphthalein. Therefore any results found after testing with those chemicals would have a high chance of being wrong and would therefore weaken any case against a suspect instead strengthening it."

"Pass. Jacob Clark."