Sarah had a vague feeling that Arthur was hiding something, but what he asked for wasn't a big deal, so she had no reason to object.
Arthur returned to his desk and saw that the report was neatly placed there. He silently thanked Sarah and then began to flip through the report, reading it very seriously.
The poison remaining in the syringe was confirmed to be the same kind, without a doubt. Because this was a homemade poison, it was basically impossible for them to be just "similar."
It was when Arthur got to the report about the fingerprints on the syringe that he frowned.
Everyone knows a syringe is made of three parts: the needle, the cylindrical barrel, and the plunger. Not to mention the needle, the cylindrical barrel always has two protruding flanges at the end, which are used as a support for the index and middle fingers to grip, while a thumb pushes the plunger into the barrel.
That's the standard way to use a syringe.
And in the report, it was clearly stated that Scott's index and middle fingers were on the two protruding flanges of the barrel, and his ring finger was on the bottom of the plunger.
Clear evidence.
Arthur was dazed for a moment, then he suddenly rummaged through a drawer, pulling out the victim's previous case file.
Although he wasn't too fond of examining physical evidence, that was just a personal preference. As an investigator, this was still a skill Arthur couldn't do without.
He flipped through the file, starting with the analysis of the victim's last steps.
Although there was no surveillance camera that recorded the actual scene, through the direction of the shoe prints, Arthur could still tell which way the victim turned when he was injected with the poison and when he died.
Here, Arthur saw that the victim was injected with poison when his toes were pointed toward the door. After that, he slowly backed away, his steps faltering, and his fingerprints were on the armrest of a chair on his left. Finally, the priest retreated toward the center of the church and lay there. Arthur could clearly see two handprints on the floor as he slowly sat down and then lay on his back.
So, where was the killer? Or more accurately, from what position did he inject him with the poison?
It was certain that the killer and the priest were in a conversation, so the possibility of the killer standing in other positions to inject the poison was much lower than the killer standing right in front of him. And as he had previously assumed, it was very likely that the killer took advantage of a close-contact action, like a hug, to strike and inject the poison into the victim's neck.
Next, Arthur examined the angle where the needle wound was located.
The position where the needle pricked was quite far back, slanted slightly downward if a coordinate axis was placed at the priest's neck while he was standing upright.
It was a diagonal wound, not a straight one into the neck.
In Arthur's head, he began to imagine. For such a wound to be created, the syringe must have been angled in a similar way—slanted backward.
At this point, he finally found something that didn't quite fit.
"It seems like…"
Arthur flipped the file again. The handprints found on the syringe were in a standard syringe-holding position.
And this position was quite inconvenient for creating a wound at that angle.
If the killer was standing in front of the victim and they weren't hugging, then the killer could only point the syringe forward, while the wound was slanted backward. So the previous assumption was impossible.
If the killer and victim were hugging, then the killer holding the syringe with three fingers like that could indeed create a diagonal wound like that, but with both of them so close, the killer's arm would have to be bent and awkwardly strained, which would be very uncomfortable and inconvenient.
So, the killer basically didn't hold the syringe like that.
Aside from the standard three-finger grip mentioned above, Arthur thought of another way to hold a syringe.
That was to grasp the barrel with all four fingers while placing the thumb on the base of the plunger, ready to inject at any moment.
This grip was not medically standard, but it was extremely convenient for the killer's situation at that time. Because the killer would hardly need to bend their wrist or elbow to get the needle tip in the right spot.
"Wait, it seems like I'm still missing something…"
Arthur flipped the file again, right to the page analyzing the angle of the needle wound on the priest.
This wound was not only slanted backward, but it was also pointing downward.
"If the killer was the same height or taller than the victim, then the wound would be relatively horizontal or slanted upward, because this is a relatively suitable angle if the killer reaches over the victim's shoulder to stick the syringe in. But this wound is pointing downward..."
The "room" once again appeared in Arthur's eyes. This time, it specifically depicted the moment when the priest was hugging the killer.
Suddenly, he understood.
It was the angle.
Until now, he had only considered the priest's angle when he was standing straight, which was why the needle wound could only be horizontal or upward.
But what if he was bent over?
At this moment, the "killer" in Arthur's imagination became shorter, forcing the priest to bend down to hug them. At this point, his neck would be slanted, turning the "downward" direction when he was standing straight into a "horizontal" direction when he was leaning forward. At this point, the killer could use the syringe to stab the victim's neck horizontally, so that when the victim stood up straight, the needle wound that was horizontal became "downward."
"Another piece of the puzzle put together."
Arthur mumbled, sitting dazed in his chair, with several case files scattered in front of him.
He not only realized that Scott was innocent and had been framed, but he also realized that the hypothesis that the killer could be a woman or a teenager was further solidified.
Because, clearly, based on the angle of the needle wound, there was no man in that neighborhood short enough for that to happen.
Originally, Arthur had only hypothesized that the killer acted while hugging the victim because of the priest's nature, but now, he could partially prove this to be true.
Arthur took a cigarette from his pocket and lit it, taking a drag. The smoke rushed into his throat, calming him down a little.
As an investigator, the most important thing is to keep a clear head and not let emotions get in the way.
Even though he felt that he was getting closer to the truth, until he ripped off the killer's mask, he would not let his guard down or be complacent that he had solved the case.
The curtain hasn't fallen yet.