"First, he killed the sleeping victim, who had no way to resist... and only then tore off the button?"
Hearing this, the officers felt as though their brains had twisted into knots. Jiang Xia's deduction seemed to be the complete opposite of what they had assumed.
But Mr. Jiang Xia had to be right—so why had the killer gone to all that trouble? Had he wanted to create the illusion that the two had fought fiercely?
Jiang Xia glanced at them and thoughtfully put it in simpler terms. "The fluorescence the killer used for navigation wasn't only on the furniture. It was also on the victim's heart—he smeared a bit of glow-in-the-dark paint onto the third button of the victim's shirt."
"As long as the killer followed the marks on the furniture and made it to the sofa, he could use the faint glow from the button to aim at the victim's vital point and kill him with one stab."
"Afterward, to keep anyone from noticing that there was something unusual about the button and connecting it to how he moved around in the dark, the killer simply tore it off. A button that had been lost somewhere was safer than one coated in fluorescence."
"Also, according to those who knew him, the victim had poor hygiene habits. He rarely changed clothes and rarely bathed. So as long as the killer found an opportunity in the past few days to apply fluorescence to his clothes, he wouldn't have to worry about the victim changing shirts and ruining his method of navigation."
As he spoke, a young officer ran back holding an evidence bag. "Mr. Jiang Xia, just as you said, we found this button in Mr. Nezen's locker! That room has surveillance cameras, and we've also found footage of him