Chapter 219: Two Tracks

Sitting in the Front District Criminal Investigation Team office, Jiang Yuan carefully compared the cast of Bai Yuequn's footprints with the blood prints at the crime scene, examining them repeatedly.

The one problem with footprints is that they can't definitively identify a suspect. They can get arbitrarily close, but never certain.

Otherwise, if they were like fingerprints, they could be used directly as ironclad evidence for prosecution.

Barefoot prints could be treated like fingerprints, but unfortunately, they're rarely available.

Murderers rarely kill barefoot.

Even though it's not 100% certain, from Jiang Yuan's perspective, this level of match was sufficient to confirm Bai Yuequn's status as a suspect.

If someone this close still isn't the killer, then it's just another coincidence.

Considering Yuan Yutang was only in his twenties, a diamond-shaped penis ground from a vajra couldn't have had many lovers or rivals, and a mouth that drove women wild wouldn't have angered many people—so what's the probability that someone with a motive to kill would also have matching footprints?

So when Front District Criminal Investigation Captain Lei Xin mentioned an alibi witness, Jiang Yuan immediately questioned the witness.

Physical evidence rarely lies; witnesses lie too easily.

Still, this was the first time he'd encountered such a situation, and even he felt some doubt.

What if?

As Jiang Yuan frowned over the footprints, Huang Qiang walked over with a smile.

"Stuck?" Huang Qiang looked at Jiang Yuan.

"Not exactly stuck, but…" Jiang Yuan didn't know how to explain it to Huang Qiang.

"I don't understand technology or footprints, but from your tone, Bai Yuequn's prints match the scene's pretty well?" Huang Qiang asked.

"Yes." Jiang Yuan, holding back nothing, continued: "Height matches, he wears lift shoes, shoe size matches, he wears larger shoes; weight and age match too. I also watched the surveillance footage—his stride and gait are nearly identical. If he were a stranger…"

Huang Qiang smiled, gently pressing down Jiang Yuan's waving arm, and whispered: "No need for 'if.' It's him."

"Huh?" Jiang Yuan was surprised—he hadn't dared to be this certain.

"You yourself explained the CSI effect to me before. Now you're falling into it." Huang Qiang smiled. "Do you really need DNA or fingerprints to confirm a killer? Do you need 100% certainty to prosecute? If that were the case, how would we have solved cases twenty years ago?"

Jiang Yuan said: "So back then, you relied on confessions?"

"Confessions aren't 100% either. Coercion isn't just an American thing." Huang Qiang waved his hand. "We have enough leads."

"Then Captain Lei…"

"He's just gotten involved and doesn't know the case well yet. Plus, the crime happened in his jurisdiction—he's thinking more cautiously. Don't bother him now."

"Then…"

Huang Qiang said: "Stop fixating on the footprints."

"Then what should I look at?"

Huang Qiang said: "Look at anything. We have a saying in criminal investigation: one piece of evidence isn't enough. In my terms, a case must have multiple pieces of evidence. The hardest part—we've already done it: we've found the killer. Now we just need to prove it."

Huang Qiang counted on his fingers: "Assume Bai Yuequn killed him. Assume his alibi is fake. The key is: can we prove it? Can we lock him down with physical evidence?"

Jiang Yuan immediately pulled himself out of his narrow tunnel of thought.

Indeed, the killer had left a great deal of evidence. If they could link any of it to Bai Yuequn, the case would be solved.

Assuming someone is the killer, then proving it—that's the most common method in criminal investigation.

In fact, most cases are solved this way. As I said before, experienced detectives can spot a first-time killer at a glance.

That's why residential burglary is often harder to solve than residential murder—easy burglary cases are usually due to sloppy, unprepared suspects. Some professional thieves, having gone too long without arrest, grow careless, make mistakes, and with high workload, they slip up.

The Hangzhou wife-killing case, and countless other wife-killing and husband-killing cases, were nearly identical.

Police spend most of their time and energy on proving connections.

The Yuan Yutang murder case isn't complicated at all.

If Bai Yuequn is the killer, he's just set up some false trails.

He switched to rarely-worn shoes, wasn't injured at the scene, and has an alibi—but all these actions require massive effort.

The more he does, the more likely he is to make a mistake.

The more likely he is to leave behind evidence.

Jiang Yuan couldn't help recalling the autopsy images from hours earlier.

Yuan Yutang and his ex-boyfriend were both stabbed to death with the same double-edged dagger. The blade was long—at least thirty centimeters—and razor-sharp. Most strikingly, after over thirty stabs, the blade's sharpness hadn't dulled.

Such quality in ancient times would've been a divine weapon; even today, it's an expensive military-grade dagger.

In China's environment, such a dagger is both easy and hard to buy—it's still likely to leave traces.

Weapon: military dagger.

Jiang Yuan wrote those two words in his notebook and drew a line under them.

Huang Qiang nodded but said nothing.

He'd seen the autopsy report too. The military dagger explained why the killer could kill two people with dozens of stabs and remain unharmed.

Many novice killers have never even killed a chicken, let alone slaughtered a large mammal, so they don't understand how much resistance human muscle tissue offers.

Daggers and short blades are completely different from spears or long swords.

Daggers and short blades generate greater recoil. Wrong technique puts enormous pressure on the wrist and tiger's mouth.

With a long sword or spear, even a novice can gather full-body strength after a bit of practice. Not so with daggers or short blades. Plus, civilian-grade blades dull after a few stabs; too much force risks injuring oneself.

Also, killing is exhausting.

More precisely, stabbing someone is exhausting.

Like slaughtering a pig in the village—it takes several strong men to hold it down, tie it up, and it still struggles.

…

One, two, three stabs are manageable. Thirty stabs? Not easy. Later movements become distorted; the chance of error or self-injury rises.

The military dagger's sharpness helps mitigate this.

Add Bai Yuequn's calloused hands—clearly trained—and Jiang Yuan even suspected he'd prepared in advance.

Keys!

Jiang Yuan wrote those two words in his notebook again and drew another line.

Yuan Yutang's door lock showed no signs of forced entry or lock-picking. The killer must've used a key, opened the door while Yuan Yutang and his boyfriend were unconscious, stabbed the boyfriend first, then repeatedly stabbed Yuan Yutang until he died.

This is also one reason the suspect list focused on lovers and rivals.

No matter how many people Yuan Yutang worked with, none could get a key to his home.

Only lovers or rivals could reasonably obtain a key.

Blood-stained clothing.

Jiang Yuan immediately pictured the killer's post-crime actions.

The killer's cleanup was sloppy—perhaps due to time pressure. He didn't even bother with the blood footprints, just dumped a bucket of water over them.

But given the volume of blood at the scene, the killer's clothes were surely soaked. He could wash and change in the bathroom, but the discarded clothes couldn't be cleaned thoroughly in a single day.

Most people either discard, burn, or bury them.

But all those options require time.

Bai Yuequn lives in the city center—plenty of surveillance.

So his options for hiding the blood-stained clothes are limited: maybe at the bar or office.

Theater projection room surveillance!

Jiang Yuan couldn't help writing that down too.

Theater projection room surveillance is important and rarely fails for long. For it to break down precisely during Bai Yuequn's movie viewing? The probability is low—worth checking.

After writing all this, Jiang Yuan regained confidence: "I think we should start with the blood-stained clothes. Send a police dog to search Bai Yuequn's bar."

Huang Qiang said: "The smell there is too strong. Plus, Dazhuang's been assigned to Liu Jinghui. Use humans instead."

"So two lines: find the weapon and blood-stained clothes, check the theater's projection room surveillance." Jiang Yuan summarized, then asked: "Should we talk to Captain Lei?"

"I'll talk to him. He's probably figured it out by now." Huang Qiang smiled and went to assign personnel.

Jiang Yuan stared at his notebook, lost in thought.