演讲题目：How reliable is fingerprint evidence?

演讲简介：

1902年，侦探们抵达了一处惨不忍睹的凶杀现场，在那里发现了一块带有数枚血指纹的碎玻璃。他们不辞辛劳地查阅警局档案记录，最终找到了匹配对象——一名男子，此人后来对犯罪事实供认不讳。时至今日，指纹依然是刑事法庭上最为常见的证据类型之一。然而，指纹证据究竟有多可靠呢？西奥多·叶申（Theodore Yeshion，此处为音译，人名可依实际需求调整）对此展开了调查。



中英文字幕

On October 17th, 1902, Paris detectives arrived at a grisly scene.

1902年10月17日，巴黎侦探到达了一个可怕的场景。

Joseph Reibel had been murdered at his workplace.

约瑟夫·雷贝尔在工作场所被谋杀。

With no eyewitnesses, the officers had little to work from, until they discovered a shard of broken glass with several bloody fingerprints.

由于没有目击者，警察们几乎没有什么可查的，直到他们发现了一块碎玻璃碎片，上面有几个血淋淋的指纹。

An investigator manually searched the police station's fingerprint records and eventually found a match.

一名调查员手动搜索了警察局的指纹记录，最终找到了匹配的。

Henri Scheffer, who had been arrested for theft the year before, was detained and later confessed to the murder.

亨利·谢弗（Henri Scheffer）前一年因盗窃被捕，后来被拘留，并承认了谋杀罪。

This marked the first time in Europe that investigators solved a crime using fingerprints alone.

这标志着欧洲第一次调查人员仅使用指纹解决犯罪。

Over a century later, fingerprints remain one of the most common types of evidence in criminal courts.

一个多世纪后，指纹仍然是刑事法庭上最常见的证据类型之一。

But just how reliable are they?

但它们到底有多可靠呢？

Humans, like other climbing species,

人类和其他攀岩物种一样，

are born with patterns of raised ridges and recessed furrows not only on their fingers but also along their hands and feet.

生来就有隆起和凹陷的图案，不仅在手指上，而且在手脚上也有。

These friction ridges help provide a firmer grip, especially on wet surfaces, and increase our sensitivity to touch.

这些摩擦脊有助于提供更牢固的抓地力，尤其是在潮湿的表面上，并提高我们对触摸的敏感性。

They begin to develop in the womb at about seven weeks, when the skin on the hands and feet swell to form smooth raised pads.

大约七周时，它们开始在子宫中发育，此时手脚上的皮肤肿胀，形成光滑的隆起垫。

At around ten weeks, deeper layers begin to grow faster than the upper layers, causing the pads to buckle and fold.

大约十周时，较深层开始比上层生长得更快，导致垫弯曲和折叠。

This folding is guided by genetics and environmental factors and continues over the next several months.

这种折叠是由遗传和环境因素引导的，并在未来几个月内持续。

Scientists have yet to fully understand the exact environmental factors at play,

科学家尚未完全了解确切的环境因素，

but it's their randomness that leads to the formation of unique fingerprint patterns.

但正是它们的随机性导致了独特的指纹图案的形成。

In fact, many experts believe it's improbable that any two fingerprints, past or present, are exactly alike.

事实上，许多专家认为，任何两个指纹，无论是过去的还是现在的，都不可能完全相同。

They're even different among identical twins.

同卵双胞胎之间的情况甚至也有所不同。

People have likely known about the individual nature of fingerprints for centuries,

几个世纪以来，人们可能就知道指纹的个体性质，

but it wasn't until the late 1800s that scientists began studying and classifying their different features.

但直到1800年代末，科学家们才开始研究和分类不同特征。

By the early 1900s, prosecutors began utilizing fingerprints in courts, forever changing how detectives approach and analyze crime scenes.

到20世纪初，检察官开始在法庭上使用指纹，永远改变了侦探接近和分析犯罪现场的方式。

Today, investigators often begin by searching for visible prints.

如今，调查人员通常从寻找可见的指纹开始。

These include patent prints, left by transferable substances like blood or dirt, and plastic prints, which are impressions in soft,

这些包括专利印刷品，由可转移的物质，如血液或污垢，和塑料印刷品，这是在软、

malleable materials, like caulking, wax, or even a newly painted fence.

可塑性材料，例如堵缝、蜡，甚至新粉刷的栅栏。

However, most fingerprints aren't visible to the naked eye.

然而，大多数指纹肉眼看不到。

These are called latent prints, and they're composed of the water, oils, proteins, and salts that ridge patterns leave on surfaces.

这些被称为潜印，由指纹在表面留下的水、油、蛋白质和盐组成。

They can be revealed by dusting with a fine powder, which sticks to the water and oil trail.

他们可以通过用细粉除尘来揭示，细粉会粘在水和油的痕迹上。

If surfaces are porous or difficult to dust, investigators use chemical developers like Ninhydrin, which reacts with proteins left by fingers.

如果表面是多孔的或难以除尘的，研究人员会使用诸如化学显色剂，它会与手指留下的蛋白质发生反应。

Forensic scientists continue to develop more sensitive and surface-specific tools.

法医继续开发更敏锐和针对表面的工具。

For example, one experimental technique uses an electrical charge to capture the corrosion that fingerprint salts leave on metals,

例如，一种实验技术使用电荷来捕获指纹盐在金属上留下的腐蚀，

even if they have been wiped down.

即使它们已经被擦掉了。

Once investigators have collected prints, then they get to work matching them with potential suspects.

一旦调查人员收集到指纹，他们就会开始将其与潜在嫌疑人进行匹配。

In certain cases, investigators will use automated computing systems that can narrow down potential matches found in national fingerprint databases.

在某些情况下，调查人员将使用自动化计算系统来缩小国家指纹数据库中发现的潜在匹配范围。

Certified experts then compare minor fingerprint details, such as how the ridges branch and intersect, and the spacing of oil pores.

认证专家然后比较次要的指纹细节，如脊如何分支和交叉，以及油孔的间距。

Any result must be blindly verified by a second expert before information is handed over to justice departments.

任何结果都必须经过第二位专家的盲目验证，然后才能将信息移交给司法部门。

The fact that fingerprint patterns are unique for every individual makes them particularly strong evidence in criminal cases.

指纹图案对每个人来说都是独一无二的，这使得它们在刑事案件中尤其有力。

However, the system isn't infallible.

然而，这个系统也不是绝对可靠的。

Prints are often smudged, distorted, or overlapped with other prints, which can make matching more challenging.

版画经常被弄脏、扭曲或与其他版画重叠，这可能会使匹配更具挑战性。

And it's prone to human error— one 2011 study found that fingerprint experts falsely identified two different fingerprints as a match 0.1% of the time.

而且很容易出现人为错误--2011年的一项研究发现，指纹专家错误地将两个不同的指纹识别为匹配的比例为0.1%。

While this may seem low, the stakes are high for a wrongly accused defendant.

虽然这看起来很低，但对于一个被错误指控的被告来说，风险很高。

Further, there's no universal standard on the number of ridge details that experts must analyze to make a match.

此外，对于专家必须分析以进行匹配的指纹细节数量，没有通用标准。

Many investigators stress that no conviction should be made on fingerprint evidence alone.

许多调查人员强调，不应仅根据指纹证据定罪。

For these reasons, forensic experts continue to work to improve and standardize the fingerprinting process.

出于这些原因，法医专家继续努力改进和标准化指纹识别过程。

After all, when it comes to investigating crime, fingerprints have certainly left their mark.

毕竟，在调查犯罪方面，指纹确实留下了痕迹。