Bai Ye's unique physiology meant he could only absorb nutrients through blood. When the nuns, devout followers of God, discovered his "flaws," they branded him a child of the devil!
The orphanage director, hoping Bai Ye would stay, seemed to have reached a tacit understanding with him: as long as Bai Ye behaved and didn't bite anyone, the director would secretly feed him animal blood. Though it was no match for human blood in taste, it was enough to keep him alive.
After growing up, Bai Ye escaped the orphanage. After years of hiding, he began his revenge against the prostitutes. I suspect he felt little gratitude towards the director; instead, he harbored deep resentment — resentment for being brought into this world, for the miserable childhood he endured. Yet the director's guilt over his own son's fate was profound...
This guilt turned him into Bai Ye's accomplice, covering up for him and ensuring he avoided the police.
These are just my speculations, but I believe the truth is not far from this. After hearing my explanation, Huang Xiaotao angrily declared, "Whatever their reasons, we must arrest this father and son!"
Soon, Wang Yuanchao returned with the items I requested. I took a basin and carefully cut open the ink sac of a squid, letting the ink drip inside. Then I poured in linseed oil and stirred to fully mix the two.
Wang Dali asked curiously, "Why buy a squid ink sac when there's ink on the table already?"
I answered, "You don't understand. Squid ink is an ancient medicinal ingredient known as 'fuchong mo' (ink from the belly). It's recorded in the Compendium of Materia Medica. It has two special traits: first, it's light and doesn't damage ash shapes; second, it contains phosphorus, so it can glow!"
"Glow?" Wang Dali's eyes widened.
...
I borrowed a straw from Xiao Zhou and sucked up a bit of the mixed squid ink. I asked him to prepare a camera, set the exposure to maximum, and ordered the officers to turn off all the lights at the scene.
Even with the lights off, some faint light filtered through the windows. I told someone to pull the curtains as well, plunging the room into darkness.
"It's so dark. Should I shine a flashlight for you?" Huang Xiaotao asked.
"No need. I can see!" I activated my '洞幽之瞳' (Mystic Insight), taking in everything in the room.
Xiao Zhou said, "I still can't see anything."
I guided him to a spot and told him to hold the camera ready, pressing the shutter when I said.
Then I dripped the squid ink mixture onto the ash and waited about ten seconds. Slowly, glowing markings appeared on the ash, prompting gasps from everyone.
"Quick, take the shot! The glow won't last long!"
Xiao Zhou pressed the shutter. After taking the photo, I told someone to turn the lights back on.
Xiao Zhou used a digital camera. After checking the photo and seeing the result was good, he asked the tech team to upload it to a computer for restoration in Photoshop. Under eager watch, the ash fragments formed a line of words — an address: "No. 48, Nanqiang Road."
Huang Xiaotao exclaimed excitedly, "This might be the crime scene tonight! Xiao Xu, you and a few officers stay here to keep watch. The rest of us follow me!"
We rushed to No. 48 Nanqiang Road — a residential building. Huang Xiaotao prepared to knock on doors and ask questions, but I said that would alert the culprit. Instead, I told Xiao Zhou to get the ultraviolet lamp.
I handed the UV lamp to Wang Dali, showed him how to use it, and asked him to hold it high. I then pulled out my red umbrella, opened it slowly, and rotated it to a certain angle. Through the paper of the umbrella, the light projected a chaotic trail of footprints on the ground.
"Isn't this umbrella only for forensic examinations?" Huang Xiaotao asked curiously.
"Far more than that," I replied.
"How convenient! I wish everyone in the tech team had one," Xiao Zhou said enviously.
I thought to myself, "No chance. Making this umbrella took a lot of time, and it contains secret formulas from the Song family — I can't reveal them."
The building was busy; footprints everywhere. Huang Xiaotao frowned, "Which ones belong to the killer?"
I looked closely and pointed to one trail, "This one — heavy left foot, light right foot — definitely left by the director!"
We followed the footprints to the fourth floor. They vanished in front of a door. Just as I was about to pick the lock, Huang Xiaotao kicked the door open, drew her gun, and led the charge inside. The others quickly followed.
As they searched the room, Huang Xiaotao suddenly screamed. Then came a fluttering noise — a swarm of black bats flew out, startling Wang Dali and me.
"Song Yang, we're too late!" Huang Xiaotao's voice came from inside.
I entered the bedroom and saw a woman's corpse lying there, wearing a floral dress, her skin pale as paper, with two bite marks on her neck — the same as the previous victim.
The ceiling was covered with bats. Although many fled due to the police's intrusion, plenty remained.
The bats looked like messengers from hell, a dense black mass twitching occasionally, their small eyes glowing eerie green. Anyone with trypophobia would be terrified.
I felt disheartened. If we had found out the director was an accomplice earlier, this girl might still be alive.
But the body had to be examined. I told Huang Xiaotao, "Wang Dali and I will stay to examine the corpse. You take the others to search nearby."
"Are you two sure you can handle it alone?" she asked worriedly.
"No problem. The killer won't come back," I assured her.
"But what about those bats…" Huang Xiaotao glanced at the ceiling.
"They're ordinary bats — harmless," I said dismissively.
"Alright, I'll leave Wang Yuanchao here to protect you."
After she left with the others, the tech team began collecting evidence. I rolled up my sleeves, put on gloves, checked the corpse's pupils, listened to bone sounds, and estimated the time of death to be around two hours ago.
Though I doubted we'd find anything useful, I still proceeded. I told Wang Dali to take some rice paper and camellia oil from the bag and perform the 'oil-paper fingerprint extraction' method.
Wang Dali asked, "Why not just use your magic umbrella?"
"Forensics requires adapting methods to the situation. No single technique works every time," I explained.
Surprisingly, this method revealed clues. The fingerprint on the rice paper showed faint ridges.
Xiao Zhou rushed over to photograph it, "This can't be the same person!"
"No," I said after comparing, "It's definitely Bai Ye. Recently, he's been absorbing excessive blood protein, causing his skin to secrete oil again — something he might not even realize."
Wang Dali suggested, "Could it be that the killer drinks blood to cure his strange condition?"
I pondered, "Possible. But since he can secrete oil now, let's try a simpler approach."
I had Wang Dali turn on the UV lamp and slowly spin open the red umbrella, simulating sunlight.
The bats above, disturbed by the UV light, fluttered wildly and flew out the open window, making everyone scream.
Under the umbrella's eerie red glow, faint fingerprints appeared on the doorframe, table, and a water glass.
Xiao Zhou started following me and I told him, "Stay here and check the water in that glass for DNA."
"Okay!" he nodded.
As I walked out, I saw the same fingerprints on the stair railing — and they were leading upstairs.
Wang Dali's eyes widened, "The killer didn't go downstairs... he's still in the building."
Wang Yuanchao, smoking by the door, immediately stubbed out his cigarette, gripped his pistol, and looked at me expectantly.
Seizing the moment, I decided, "The three of us will go upstairs and catch him!"