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How did detectives solve the case of the bloody motel? - Theodore E. Yeshion - Video học tiếng Anh
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How did detectives solve the case of the bloody motel? - Theodore E. Yeshion
How did detectives solve the case of the bloody motel? - Theodore E. Yeshion
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0:07
Officer Stone approaches the dimly lit motel he’s been called to investigate.
0:13
Outside the shattered windows and broken door,
0:16
the motel manager tells him the room was rented to Frank Carter,
0:21
who was last seen entering the motel three nights earlier.
0:24
While Carter doesn't have the cleanest record,
0:27
he's never been arrested for a violent crime before.
0:30
Yet as Stone scans the crime scene,
0:33
he sees a disorderly room, visible red-brown stains and a partial shoe track.
0:40
All these details hint at a bloody struggle,
0:44
but there aren't enough clues to say exactly what happened.
0:48
After calling in a detective and a crime scene investigation team
0:52
to inspect, photograph, sketch, measure, and collect all the obvious evidence,
0:57
the investigators decide their next move.
1:01
It's time to apply luminol.
1:05
Luminol, also known as 3-aminophthalhydrazide,
1:09
was first introduced as an investigative tool
1:12
in 1937 by a German forensic scientist named Dr. Walter Specht.
1:19
Almost a decade earlier,
1:20
research found that when mixed in a solution with an oxidizing agent
1:24
and exposed to certain compounds,
1:27
luminol molecules rapidly oxidize, become excited,
1:31
and emit a faint blue-white glow
1:35
as they return to their normal state.
1:37
This process is called chemiluminescence,
1:41
and Specht discovered he could trigger it by exposing luminol to hemoglobin,
1:47
a protein found in red blood cells.
1:49
So by spraying the solution in a dark crime scene,
1:53
he could illuminate even the faintest traces of blood.
1:58
This is what Officer Stone is hoping to do back at the motel.
2:02
The lights are switched off,
2:03
and the forensic team sprays luminol across the walls, floor, and ceiling.
2:09
The chemiluminescence only lasts about 30 seconds,
2:12
so our investigators need to keep spraying
2:14
as they track blood through the crime scene.
2:17
But if they find a trail,
2:19
the specific patterns of blood could help reconstruct what might have happened.
2:24
In some crime scenes, luminol might reveal footprints or drag marks.
2:29
It can show larger drips associated with slowly bleeding wounds,
2:33
or fine spatter suggesting high-impact wounds
2:37
from firearms or motorized tools.
2:40
The absence of a reaction can be just as informative,
2:43
indicating when people or objects blocked blood from hitting a surface.
2:48
And since luminol will react even if the blood is extremely diluted,
2:52
it's almost impossible to clean a bloody crime scene well enough
2:56
to prevent chemiluminescence.
2:59
In fact, a skilled investigator can even use these lingering patterns
3:04
to identify attempts at blood removal.
3:08
In this case,
3:09
Officer Stone finds spattered spots of blue light on the floor,
3:14
suggesting an impact wound and a struggle.
3:17
Shoe track impressions and a glowing handprint on the kitchen countertop
3:21
line up with the drag mark on the floor.
3:24
Following the trail from the foot of the bed,
3:26
the investigators end up in the parking lot,
3:29
suggesting the victim was placed inside a vehicle.
3:33
These stains make a strong case for the narrative revealed by luminol.
3:38
But investigators have to be careful
3:40
since the chemical’s high sensitivity is a double-edged sword.
3:44
Not only does luminol react to very old bloodstains,
3:47
with some cases showing chemoluminescence on objects thousands of years old,
3:52
it can also react to cleaning agents like bleach or materials containing copper.
3:58
This is why luminol is what's called a presumptive blood test.
4:03
It indicates the possible presence of blood,
4:06
but a confirmatory test with chemicals that only react to hemoglobin
4:11
must be done to prove it.
4:13
If a positive reaction for blood is confirmed, however,
4:17
DNA tests can be especially useful for identifying and eliminating
4:21
potential suspects.
4:23
Officer Stone submitted a DNA sample from the motel for that exact purpose,
4:28
and the results found exactly the clue he needs.
4:32
The blood belongs to Frank Carter,
4:35
suggesting that he may be the victim, not the culprit.
4:40
Stone is mulling over this new evidence
4:42
when he gets a call from a local state trooper.
4:45
After pulling over an erratic driver,
4:48
the trooper noticed what appeared to be bloodstains on the rear bumper.
4:52
The car's trunk was empty,
4:54
but luminol testing later revealed traces of blood throughout the car.
4:59
One more DNA test confirms Stone’s suspicions:
5:03
Carter was the victim.
5:06
And faced with this overwhelming evidence, the car’s driver confessed to the crime.
