The rooftop of the abandoned apartment building was located in a rather remote area. Because the building sat on elevated ground, the view from the top was exceptionally wide and open.
The railing around the rooftop was so low that even children could lean half their bodies over it. Ritsu narrowed his eyes slightly as he surveyed the river the children had mentioned. Estimating by sight alone, the distance was roughly 300 yards, an impressive level of marksmanship for an average person.
According to what Mitsuhiko had said, there had been four people on the rooftop altogether. Aside from the man carrying the rifle, the other three were armed as well.
A four-man armed group like that most likely pointed toward a kidnapping case involving firearms.
Threatening a sniper into carrying out an assassination mission? That sort of business was something he knew very well.
Ritsu turned toward the three children still curiously looking around and smiled.
"Kids, what comes next isn't something you should get involved in anymore. Do you need big brother to call a police car to take you home?"
Ride home in a police car?
Ayumi immediately looked disgusted. "No way, no way! We can take the train home ourselves!"
"Yeah! Riding in a police car makes it look like we're bad kids!"
"Goodbye, Onii-chan! I hope tomorrow's newspaper shows you catching the bad guys!"
Whether they were afraid of being sent home in a patrol car or something else entirely, the three little troublemakers vanished down the stairs in the blink of an eye.
Only after watching them leave did Ritsu begin thoroughly searching the rooftop.
If the man firing the rifle had truly been under duress, there was a good chance he would have left behind some sort of clue. Even if the odds were slim, most people would still try to send out a distress signal.
After circling the rooftop once without finding anything, Ritsu was heading down the stairway when he unexpectedly spotted an ultra-thin calculator wedged between cracks in the concrete.
Pulling gloves from his pocket and putting them on, he bent down and picked it up, only to discover a string of completely irregular numbers displayed on the screen.
3135134112.
What the hell was this?
He couldn't crack the code immediately, but one thing was certain, the shooter really had been threatened. This was a distress signal left behind by him.
Ritsu sighed, slipped the calculator into an evidence bag, and headed downstairs with one hand in his pocket.
Looks like his rare vacation day had turned into forced overtime again.
"Seriously…" he muttered quietly. "Why has Tokyo's crime rate been going up lately?"
Taking a taxi to the Metropolitan Police Department, Ritsu rode the elevator up to the ninth floor. Pushing open the large office doors, he headed straight toward his desk.
Hayasaka, who hadn't taken the day off, looked at Ritsu in confusion. "Inspector, weren't you supposed to be off today?"
"There's likely been a coercive shooting incident. The criminals probably kidnapped someone and forced them to carry out an assassination-style shooting task." Ritsu took the calculator out of his pocket and continued,
"This was left behind at the scene as a distress signal. I haven't cracked its meaning yet. First, help me pull recent missing persons reports."
"If it just happened recently, then it probably hasn't reached the forty-eight-hour threshold required to officially open a case yet. I'll contact the operators, they'll have records of incoming reports." Hayasaka reacted immediately and picked up the desk phone to dial the internal line.
Passing nearby, Miwako overheard the conversation and curiously asked, "Inspector Onizawa, how did you even run into something like this?"
"Oh, I was looking for a good restaurant when I ran into three kids. They were the first witnesses who saw the rifle shot."
"I see." Sato smiled. "You're really a responsible police officer. A lot of cops wouldn't believe something children say."
She genuinely admired officers who treated children kindly. Well, admired in the sense of respect.
Her tastes were still fairly traditional, so even though Ritsu was undeniably handsome, his white hair and crimson eyes weren't exactly her type. He looked more like the sort of anime protagonist middle schoolers obsessed over.
'Wait a second… Didn't Inspector Onizawa recently get some kind of nickname around headquarters?'
For the life of her, she couldn't remember what it was.
"Isn't being a police officer about never overlooking any possibility?" Ritsu replied calmly. "That's the only way to lower crime rates and solve cases quickly."
"If every police officer were like you, Inspector, the crime rate would probably drop dramatically." Sato walked back to her desk, took a sip from her teacup, and asked, "By the way, haven't you eaten lunch yet?"
"I'll think about lunch after cracking this thing." Ritsu raised the calculator in his hand.
Less than three minutes later, Hayasaka received all recent missing-person reports from across Tokyo through the operator network. Roughly thirty percent of them were unofficial reports that hadn't met the formal filing requirements yet.
After filtering through the cases, Hayasaka quickly identified the most likely missing person connected to the incident. Taking out her cellphone, she called the number left by the reporting party. Once she confirmed the missing person's identity, she became certain they had found the right man.
"Inspector Onizawa, we found the missing person."
"Go ahead."
Hayasaka pulled up a police ID photograph with a blue background on the computer screen and explained,
"After filtering the reports, I narrowed it down to this man: Yamabe Koichi, an officer from headquarters. He used to compete in Olympic rifle shooting, which perfectly matches the circumstances."
"Mm. How did he go missing? Were there any other missing persons connected to him?"
"According to his mother, Officer Yamabe was on vacation with his girlfriend, Onodera Eri. They were supposed to come home for dinner last night, but neither returned and both of their phones were turned off. His mother reported them missing at 8:10 this morning."
Now that they had identified the missing person, the investigation became far easier. But the most important thing at the moment was still the calculator in Ritsu's hand.
He stared at the string of numbers for a long while, ruling out all the complicated decryption methods.
If Yamabe had noticed those children watching from afar, then he would absolutely have chosen the simplest possible method, something easy to understand yet subtle enough not to attract the kidnappers' attention.
At that thought, Ritsu suddenly flipped the calculator upside down. Looking at the display from the reversed angle, the corner of his mouth lifted slightly.
'So that's what it meant.'
Without revealing the answer immediately, he handed the calculator to Hayasaka and asked, "Any ideas what these numbers might mean?"
Hayasaka wasn't especially good with numbers. She shook her head. "There's no pattern at all. I can't figure it out."
"Don't focus on the logic of the numbers themselves. If you were Yamabe and only had an old-fashioned calculator, what sort of numbers would you use to send a distress signal?" Ritsu felt it was necessary to teach Hayasaka some practical investigative techniques.
Sooner or later, he would leave the Metropolitan Police Department, meaning she needed to grow stronger and faster.
"A distress signal would definitely need to reveal the mission location somehow," Hayasaka muttered while staring at the numbers. "And the code can't be too obvious, or the criminals would notice… Do you think maybe 162 refers to a highway or prefectural route?"
"Your line of thinking isn't bad," Ritsu said, shaking his head slightly. "But think simpler. Like the kind of code children could understand."
"A code children could understand?"
Hayasaka stared at the calculator in her hands. Suddenly recalling how she used to prank the servants at home as a child, she flipped the calculator upside down and exclaimed,
"211HEISEIE!"
Looks like she had successfully solved it.
With one hand in his pocket, Ritsu prepared to report the situation to his superiors and request access to a helicopter and a sniper rifle.
However, contrary to her usual cool beauty persona, Hayasaka tilted her head adorably and asked, "What exactly is HEISEIE supposed to mean?"
"…"