The Science of Murder

Beta: Stazzles-Otouto

Kinematics

This was a rare occurrence, Mouri Kogoro, Mouri Ran and young Conan-kun had been invited to a crime scene, rather than having been a witness. Seeing a crime scene from an observers perspective instead of an inside source was quite a novel experience for all three of them.

"Why are you here brat?" Mouri moaned as Conan followed behind him towards the police officers, followed dutifully by Ran.

"Because Conan-kun sometimes see's things that you don't because he's small and is able to notice things that are low down and hidden; places where tall people never look" Ran said with a smile at her little charge "plus, he knows not to mess with the crime scene"

"Also, it's fun to see you work uncle" Conan chipped in with his most innocent voice. Mouri grumbled a bit before they reached the officers clustered at the edge of the road next to a broken bridge.

"Ahhh Mouri-san" Megure-keibu said as he saw the approaching man,

"Keibu-dono, you called for my assistance?" Mouri said in his most professional voice.

"Yes, as you may have seen on your way down the road there is a sign that tells all drivers that the bridge ahead is broken and there is a right-turn diversion down to the next bridge" Megure started, pointing to the bridge behind them that was indeed broken. "The road sign is about 130 metres away from the bridge to give the drivers ample time to slow down so they can turn even when going at the speed limit of 60 mph"

"132 metres keibu" Takagi said, appearing at their side and winding up a large reel of measuring tape.

"Ahh thank you Takagi" Megure said

"Why are you telling us this?" Ran asked, confused at the apparent unneeded details.

"Well, this is relevant to the crash Ran-kun" Megure said kindly "The driver of the crashed vehicle was Fukane Aoji, 21 year old male who was apparently driving home from work at 5am this morning from his job as a night guard at the Beika Museum. The speed camera at the corner clocked his speed at 67 mph, 7 mph over the limit, if he had not been speeding we would not have known his speed at all which would not have caused all this confusion"

"Confusion?" Conan asked

"Yes Conan-kun, Fukane-san should have seen the sign and been able to slow down and turn for the diversion but he did not, there are skid marks on the road to show that he pressed the brakes very sharply and going at 67 mph he should have been able to come to a complete stop in about 70 metres, but the thing is he didn't start braking until he was 81 meters away from the bridge and therefore should have stopped about 10 metres before the bridge, yet he didn't."

"And you can't work out why it took him a long time to start braking or why the skid marks are so long?" Conan asked, "Maybe there was something wrong with the brakes?"

"The car has been retrieved and there are no signs of tampering" Takagi reported. Conan wandered off while Mouri asked more about the man.

"Car stopping distances compose of two things; one is the braking distance of the car itself, and the other is the thinking distance of the driver. In other words, how long it takes the driver to see an obstacle and push the brakes, the reaction time…if the car was travelling at 67mph which is 30 metres a second, and the average reaction speed for a young male is 0.65 seconds it would make a thinking time of 19.5 metres in an average mass car of 900kg. But he was exactly 51 metres past the sign before he began braking, so where did the extra 31.5 metres come from?...The average braking distance for that speed would be 70 metres, 72 if I am exact so he should have been able to stop just before the bridge…" Conan pondered as he wandered around the site which had been cordoned off by the police. "The questions are: why did he brake so sharply? Why didn't he slow down right after he saw the sign? And where did the extra 31.5 metres go?" Conan wandered over the bridge and looked down into the shallow river below. The car wouldn't have even been fully under water at the depth of the river, the water would have only come up about half way.

"If the brakes were definitely working fine then why did he take so long to use them? Was his thinking distance affected in some way, maybe by drugs?" Conan wandered in a roundabout way until he came to the forensic officers

"Ne, did Fukane-san have any drugs in his system?" Conan asked sweetly.

"That's what we thought too at first, that Fukane-san might have been on drugs but there are no traces of such a thing in his body" the officer said before they turned away and continued taking pictures of the area.

"For Fukane-san to have a thinking distance of 51 metres at his speed his reaction time would have had to have been 1.70 seconds, that is an oddly slow reaction speed, but there were no drugs in his system that could have slowed his reactions" he mused as he walked over to the skid marks, he inspected them closely, they seemed to get heavier in places, suggesting that the driver had pressed the brakes hard and then lifted his foot slightly and pressed down again multiple times.

"Why would someone do that?" Conan asked aloud as he walked along beside the marks, "Fukane-san lifted up and pressed his foot down on the brake five times by the look of these markings, it's almost like he wasn't concentra-" Conan stopped mid monologue. He ran over to the forensic officer again. "Ne did Fukane-san have a head injury?" he asked quickly, the officer looks at him

"Yes he did, most likely sustained when the car went over the bridge. It was on his forehead so we assumed it was from an impact with the steering wheel" the officer said

"So there isn't any chance he had a head injury before the accident?" he asked, trying to phrase it innocently. The officer and surrounding officers stopped to look at him.

"Why do you say that Conan-kun?" the officer asked

"Well because the marks are inconsistent, like Fukane-san didn't apply the same pressure on the brake the whole time which shows he wasn't concentrating and a head injury would have also slowed his reaction time, which would explain the long distance before he started braking" Conan explained, he looked up at the slack-jawed officers before scratching his head and laughing childishly "at least that's what they said in the hospital programme I was watching the other day, they brought in a woman with a concussion and were talking about how she couldn't concentrate and had slow reactions to what people were saying to her, isn't it sort of the same situation?" he asked, the officers grinned at each other and patted the boy on the head.

"Very smart Conan-kun, I would never have thought of that, a head injury would explain all the oddities of this case. I'll just call the morgue and find out if the head injury was there before the crash or caused by it" the officer turned away and pulled out a phone. Conan took the chance to go back to Megure-keibu. He listened to the officer in silence while waiting for the forensic officer to get his answers, if he was lucky he wouldn't need to knock Mouri out for a deduction show. The confirmation came five minutes later and the officer ran over to Megure-keibu from the bridge.

"Megure-keibu" the forensic officer huffed "Conan-kun was right, Fukane-san had a head injury from before the accident, that's why it took him a long time to brake, the morgue workers also noted that he had blood on his shoes which hadn't quite been washed off in the water after he went over the bridge, it could have caused his foot to keep slipping off the break pedal which explains why the marks on the road are inconsistent."

"Well that explains that, but why did he have a head injury and blood on his feet?" Megure-keibu asked the officers at large. The officers at large stayed silent and Conan silently groaned before putting on his childish voice again

"Ne ne, Keibu-san, wouldn't that mean that he was attacked and got blood on the floor then stood in it while running away?" Conan asked cutely.

"It could do Conan-kun, it would also explain why he was speeding, and his concussion couldn't have been that bad if he could still coordinate driving a car." Megure-keibu said, smiling genially at him. Takagi gave Conan a grin,

"Good job Conan-kun, you always seem to know the right things to say" Takagi said with a glint in his eyes, Conan laughed nervously while Megure-keibu spoke over Conan's head to Mouri.

"Thank you for your assistance Mouri-kun, but I think that from now it is just a matter of finding the cause of Fukane-san's head injury. Takagi will drive you home."

"Thank you Keibu-dono, can you call and tell me what happened after the case is closed?" Mouri asked, seeming to have a genuine interest.

"Yes oh course Mouri-kun" Megure-keibu said and shook hands with him, bowed to Ran and left with a friendly smile at Conan. Takagi ushered them over to a squad car and they left the scene.

The car ride home was an awkward affair, Ran and Mouri talked to each other about the case, oblivious to the silent Conan who was busily trying to avoid Takagi as the officer frequently tried to catch his eyes in the mirror. The journey finally ended and they got out of the car and waved Takagi off before retreating inside. Conan went to his room straight away and pushed the button on the side of his glasses to activate the microphone he had planted in Takagi's pocket. There was just the sound of the car as Takagi drove in silence, presumably back to the Police Headquarters, soon enough the car engine died down and new sounds echoed down the microphone of chatter and walking.

"Oh Takagi-kun, how did it go?" said a woman's voice,

"Ah, Satou-san, it went fin, Megure-keibu is going to Fukane-san's work now to find out what happened, turns out he had a concussion before the accident which was why he crashed" Takagi answered, sounding quite happy.

"They figured that out fast, Conan-kun I presume?" Satou asked

"Yes, and I won the bet, it took him 7 minutes and 22 seconds until he got that look on his face a went over to one of the officers" Takagi said while Satou groaned,

"It sounded like a difficult case, that's why everyone else bet over 10 minutes" Satou huffed.

"Ahh you shouldn't underestimate Conan-kun, that kid is special. It's rumoured that Kudo Shinichi taught him everything he knew about being a detective before he vanished." Takagi told her as their footsteps walked down another hall and into a noisy room.

"Listen up everyone!" Satou shouted over the din "Takagi-kun won, it was under 10 minutes" This was greeted by the sound of collective groans and the sounds of paper, most likely money. Conan shut off the microphone and sat down on his bed, sighing. If they were betting on him then they must not be bothered by his blatant disregard for the age: intelligence ratio, although the theories that he was so smart being because of his older self may prove to be problematic in the future. Conan flopped back onto the bed and threw an arm across his eyes,

Let them have their fun…as long as they don't start telling everyone that 'Conan' got taught by Kudo Shinichi then the Black Org should take no notice…hopefully. Best not tell Haibara about this, I wouldn't want her to panic.

Mouri got a phone call a day later from Megure-keibu. The other night guard at Fukane-san's work had been arrested, the lot where Fukane-san normally parked his car had been covered in blood and the other guard, Kenichi, had been found trying to scrub the blood away. From what Kenichi said, he had hit Fukane-san over the head in an attempt to kill him but only knocked him out and he left him to go find some rope only to find him gone when he came back. Kenichi had apparently been so angry at Fukane-san for all his "snide remarks about me and my family" that he had snapped. Megure-san told Mouri that he was seriously debating getting Kenichi put into a mental ward; it seemed that Kenichi had anger issues and had attacked many of the officers in the 24 hours he had been incarcerated.

If he is committed to a mental ward it will be as good as a prison and may even help him. Conan thought as he helped Ran set the table for dinner. Just as the three of them were about to sit down the phone ran, Mouri went to answer it.

"Moshi Moshi, Mouri Kogoro speaking...Ahhh Keibu-dono...yes of course I will…the squad car is on its way already?...okay I'll be there shortly… sure I'll bring the brat if you want me too…yes…yes goodbye" Mouri turned around to face them.

"Another case?" Conan asked.

A/N: Hope you enjoyed reading it, this one shot is part of a collection I will be writing over the next few months to help me with my physics. I will put all the one shots in the same story as different chapters so I don't overcrowd my profile. Thank you for reading and I hope the physics aspects of the chapter made sense. :D