A/N: This is my first Sherlock story, so be gentle with me. Humor me with this one, if you will. It's pre-slash, so if you don't like then don't read. If you do like, well then… R&R! Enjoy.

Jealousy: A Case Study by Detective Inspector Lestrade

As a detective inspector, Lestrade was no stranger to human emotions and reactions. He had been to too many crime scenes, had interviewed too many people, and had captured too many criminals to not be experienced in the emotions that cause people to do terrible things to one another. There were times when he told himself that nothing would surprise him anymore (Sherlock not included).

However, what he had been witnessing ever since Sherlock and John arrived at the scene made him rethink that.

Ever since the first time he had met John Watson, Lestrade has been able to see the obvious jealousy stemming out from Sherlock. At first, he thought that he was seeing things and reading the consulting detective wrong; it was Sherlock after all. He had never known Sherlock to have friends to attachments. Mycroft didn't really count in his opinion because they were blood relatives. And friends were something that the younger man didn't have or even desire. Or so it seemed to Lestrade and, well, everyone else at Scotland Yard. Needless to say, he was surprised to see John trailing after Sherlock the first day he met the doctor.

Lestrade had no idea who John was at the time or how he knew Sherlock or why Sherlock brought him along. Hell, he wasn't even sure what their…relationship was. Were they friends? Lovers? Did Sherlock even have a sexual orientation? He had no bloody clue. The only thing he knew for sure was that Sherlock didn't treat John the same as he treated everyone else. As he watched Sherlock observe the woman in pink and the room they were in, he noticed right away that Sherlock seemed…calmer? More relaxed? Nice? Whatever the term or terms that could be used to describe his behavior, it was quite obvious to everyone at the scene that John Watson was someone special. Sherlock may not have realized it (or maybe he did) at the time, but others did.

Donovan was one of them. As soon as Sherlock and John had arrived, her eyes automatically sized John up. Whatever she found, she must have liked to an extent because she wasn't as rude or harsh to the doctor as she was to the consulting detective. Granted, she was nice enough to anyone who wasn't Sherlock, but still. It hadn't been hard to see that her interest in the strange blonde had been piqued, if only for an instant.

Anderson was another one. He may have had…questionable relations with Donovan, but Lestrade could tell that Anderson liked John. A lot. Whether he favored the doctor more than Donovan, Lestrade could not say. However, it had been obvious right from the get go that Anderson had found an interest in John.

Sherlock must have noticed that as well, even if he hadn't admitted to himself yet that he actually liked John Watson and saw him as more than just another simpleton. The way he talked to Anderson with more bite than usual told Lestrade that Sherlock had been aware of Anderson's interest, even if it was only subconsciously. His remarks had been more snappish and biting ever since Anderson first met John and he was always quick to get John's attention away from the other man.

The more cases they shared together, the more Lestrade started to notice these things. The snippy remarks. The death glares. The pouting (even though Sherlock would never admit that he pouted since it wasn't something he did apparently). The touching.

Oh yes, the touching.

Every single bloody time Anderson was present at a crime scene, Sherlock would always touch John. Lestrade found it odd at first, seeing as how Sherlock wasn't known for physical contact of any sort and that he hadn't even been in an actual relationship with someone. But he always seemed to be staking his claim on John whenever Anderson was present. It used to be that way with Lestrade himself, until he told Sherlock in front, well, everyone that he had no intentions of pursuing a romantic or sexual relationship with John ever. Ever since then, Sherlock has been his usual self around Lestrade, which the detective inspector is grateful for.

Dimmock was still under scrutiny from the consulting detective, however. It made things difficult, but then again, Sherlock almost always made things difficult regardless of if it was intentional or not. Dimmock didn't make things easier on himself either. Whereas Anderson would cease any sort of conversation or gawking when Sherlock glared or snapped at him, the other detective inspector didn't. Instead, he antagonized the other to the point where Sherlock was considering dragging John and himself away from the crime scene under the pretense that John needed to eat. Considering that they had had dinner prior to arriving at the scene, everyone knew that that most certainly was not the case. Lestrade hadn't been there that time, but the story he was told by Sherlock (which was later edited by John) told him all that he needed to know.

However, the scene before him was one that he had not been anticipating. Lestrade knew that Sherlock must have been aware of his jealousy and his feelings for the doctor by this point in time. The only one who was probably still clueless was John and that was only because, for some unfathomable reason, John didn't find himself all that attractive. Ordinary, that word was often used by John when the conversation turned to his love life and, well, his life in general. He found himself to be too ordinary and average to deserve the affections of someone, anyone, else.

If only he knew…

If only John wasn't so naïve about it, actually, because from what Lestrade was witnessing, it was quite obvious that Sherlock was very jealous and very possessive and didn't want anyone touching, speaking, or even looking at John.

Currently, they were at a crime scene. A murder, actually, and as soon as Sherlock and John had stepped through the door, Anderson's eyes had been focused less on his work and more on John. Lestrade thought it was very unbecoming; after all, Anderson did have a wife and he had been having an affair with Donovan, so why would he be pinning for John? Weren't two women enough? Did he really need a man? Whatever the reason for it, Anderson's primary focusing since the two of them arrived at been John.

Sherlock, being as observant as always, noticed it right away. As his eyes looked over the body, Anderson, the blood spatter, Anderson, the room, and Anderson, John took his place beside Lestrade as was customary at this point. Together, they watched as Sherlock took everything in and began his deductions. Somehow, and for some reason, Anderson had made his way over to John and had been standing beside the doctor, leering at him practically, and was attempting to make small tall. Lestrade noticed, with a sort of approval, that John didn't seem interested in Anderson and kept his eyes on Sherlock the entire time. Suddenly, Sherlock stood up and turned around, his blue-grey eyes glaring at Anderson with a ferocity that made everyone aside from John cringe.

"Anderson, I realize that you haven't experienced release in a few weeks, mainly because of your refusal to use your wife and Donovan to achieve such a feat, but that doesn't mean you can talk to John while I'm busy trying to solve your case." Anderson opened his mouth to retort, but Sherlock didn't give him the opportunity. Lestrade could only watch in amusement as the consulting detective glared down at Anderson.

"You've been trying to get John to have coffee with you for the past few cases and I'm sick and tired of being civil about your unwanted advancements. In case your feeble mind isn't able to comprehend what I'm saying, which is the case as I can see the confusion etched across your face, allow me to spell it out for you. John doesn't want you. He will never want you and I am getting incredibly annoyed with your attempts to take him from me. They aren't working and they're unwanted so cease and desist your futile attempts at courtship." Lestrade snorted softly and he straightened up. Beside him, he heard John laugh softly before the doctor shook his head.

"What are you –"

"Just stop speaking, Anderson. All you're doing by opening that mouth of yours is proving how stupid you actually are and how right I am. Which is always, by the way, in case you haven't noticed. Now, if you don't mind, I think John and I shall be on our way. John?" Sherlock's sharp glare turned into a soft gaze as they focused on the doctor. John shook his head and moved to follow Sherlock. Lestrade took a step towards them, suddenly remembering that they were at a crime scene and that they needed the information Sherlock was able to discover.

"Sherlock, wait! You didn't tell us anything about the murder." Sherlock continued walking but John stopped and turned towards Lestrade, an apologetic look on his face as he spoke to the detective inspector.

"Sorry 'bout him. I'll make sure he texts you the information then."

"John, we need to go! It's late and you need your rest!" John sighed and Lestrade shook his head. Subtlety wasn't something that Sherlock was good at. Granted, he may already know that and either didn't care or wanted everyone to know that he was the jealous type. Most likely than not, it was probably a bit of both.

"Long day at the clinic?" Lestrade asked before John turned to leave. The doctor shook his head.

"No. I got plenty of rest before you called us. Sherlock's just being Sherlock. You know how he is."

Lestrade nodded as John left, thinking to himself that he really didn't know how Sherlock was. Not as well as John, anyway. The only thing he knew for sure was that Sherlock was jealous of anyone John came into contact with. And if the consulting detective had it his way, and he probably would, then John wouldn't be a single man for very long. For some reason, Lestrade had a feeling that Anderson asking John out for coffee may have been the straw that broke the camel's back. It was quite possible that Sherlock had finally decided to actually do something.

All he could say to that was about bloody time.