Chapter 12 Chapter Four

Next, we focus on a tall, shaggy-haired smoking man. A week after the fire, the three college students who rented the apartment went back to clean up their belongings.Soon, they reported to me that some items were missing from the room, including a TV and several household appliances. This is a good thing, I came to the pawn shop to see if anyone had sold these. Finally, the owner of a pawn shop said that a man came to pawn the items a few days ago. In Iowa, anyone pawning an item at a pawn shop must show identification with the address. The man who pawned these items was John Maimo, a 23-year-old homeless man.It is said that he likes to attend parties of all kinds.

John Maimo is a veteran of uninvited late-night parties.He always managed to find a place to sleep.Sometimes he sleeps in other people's apartments; sometimes he sleeps on other people's couches, or somewhere else. A college student who knew McMur had let John stay overnight a few weeks ago.The college student gave a general description of the situation at the time. He said that John had no friends, was not a student at school, and had no job.He may be erratic, sleeping wherever he goes, and it is not easy to find him. Just when we were having a headache, another surprise came.That day, a detective went to the University of Iowa to find out the situation, and saw him at the gate of the university.

We finally caught John, and when we checked the case, it turned out that he was on probation for forgery.While interrogating John, I noticed a burn on his nose. John admitted that he lived in the apartment when the three college students were out and stole electrical appliances from the apartment, but said he did not kill anyone or set fire to it, saying there was also a homeless man at the time Sleep in that apartment. I have also noticed this, especially in winter, when those days living on the streets become more and more difficult.This largely leads to homeless people attacking passers-by.Many homeless people defecate on the street in disregard of public morals because of this.The incidence of violent crimes such as robbery and rape by homeless people is rising rapidly. Most of them are black men, ragged and unkempt, carrying a bag with them. That is his "home" and unfolding the bedding in the bag at night , curled up in front of the store or in a corner overnight.Some of them held signs, some stretched out their hands, and what they wrote and said was the same: "Give some money to buy hamburgers." Sometimes they would come together, which would make people feel a Danger is approaching.However, others say that these people are not aggressive because they are too lazy to fight.

We made John a suspect and gathered evidence around him. After the fire, John's glasses disappeared and he got another pair, and he has a burn on his nose, which is also very suspicious. We use a lens diopter tester to measure the diopter of the lens on the pair of glasses on site.The unit of diopter is the size of refractive power, and refraction refers to the change of the direction of light when it enters another medium with a different refractive index from one medium, which is called "refraction" in ophthalmology.Its refractive index is called the refractive index or refractive index.Diopter is the size unit of refractive power, expressed in D.

An ophthalmologist examined John and proved that his eyes had the same diopter as the glasses found at the scene of the fire. The entire optometry process is like this. The doctor first "degrees" John's eyes. When calculating the real degree of his eyes, the professional optometrist first uses a computer optometry instrument to calculate the full eye degree and astigmatism of Maimo's eyes. Then, the "measurement" was carried out on Maimo, that is to measure the life degree that Maimo is most suitable for use.A professional optometrist, like a friend who can stick to Mai Moxin, has a detailed understanding of his age, nature of work, living habits, etc.Then adjust the "life degree" that is most suitable for daily use.

The last thing is to "balance" Maimo, which is to adapt to the prescription of the glasses to be worn. After the professional optometrist has mastered Maimo's real prescription and life prescription, he will try it on with a test film stand. On the one hand, he will improve his eyesight. Precise fine-tuning and adjustment to balance the parallax of the left and right eyes, on the other hand, it also allows him to adapt to future glasses. More importantly, we need to compare the results of this inspection with the test results of the pair of glasses at the scene. Now the situation is completely clear, even without John's excuse, the glasses at the scene belonged to him.

Because John is short-sighted and can only see with glasses, he would never leave them lying around.Finding his glasses at the scene of a double homicide and arson took on special significance, then. We needed more evidence, and I was analyzing the cigarette butt again in the lab because I suspected it was the one that started the apartment fire. So, can the murderer's DNA be found on this cigarette butt? Colleagues in the laboratory carefully peeled off the paper on the cigarette butt filter, and then separated the human cells stuck to the paper. This time, we obtained the biological samples necessary for DNA testing from the cigarette butts.

Tests showed that the DNA from the cigarette butts matched that of John Mammo.Statistically speaking, the chances that the DNA on a cigarette butt belongs to someone else is so small that it is almost negligible. Still, John admitted to having been to the apartment, so it's no surprise that his glasses and cigarette butts were found there. It seems that he is quite stubborn, which means that we need more evidence to make him speechless. That's when Maria's leather jacket found in the apartment comes in handy. Andre inspected the leather jacket under high-intensity lights, but found no fingerprints.He hung the leather jacket in a special cabinet.Then put some cyanoacrylate adhesive inside the cabinet.This is a low-temperature curing, single-component, easy-to-dissolve adhesive, which can quickly polymerize under the action of moisture between the two bonding surfaces, complete the curing and bonding under very light pressure, and bond all the parts in an instant. Materials such as metal, plastic, ceramic, wood, leather, natural or synthetic rubber.

The leather jacket was fumigated for about 10 minutes in the fumes from the heated adhesive.Under the action of cyanoacrylate adhesive gas, the print on the surface of the object will appear white, and if there is a fingerprint, it can be seen through the ink fingerprint card. To our surprise, the leather jacket revealed a mutilated shoe print that had been dyed to fluoresce under forensic lights. We compared this shoe print to the soles of John's shoes confiscated in custody and found they were identical in size and shape. Generally speaking, such shoe prints rarely occur on items. There must be something dirty on the soles of the shoes, or something is stuck on the leather jacket. When the shoes step on the leather jacket, the leather jacket is taken up.And being able to bring the leather jacket up from under the heels means that the dirt is a sticky substance.We picked up the shoe and examined it over and over again, finding a tiny piece of evidence in it that told us exactly what had happened to Laura and Maria.

There was a very small reddish-brown stain on the side of the sole of John's shoe, which I thought might be blood. Andre used a swab soaked in disinfectant to extract the stain, and then performed a DNA test.It turned out that the DNA from the blood on the shoe was exactly the same as Maria's. Maria's friend once said to me: "This shoe can make us feel more sad. The criminal killed Maria, and Maria's blood got on his shoe." This discovery is very important, showing that John had contact with Maria.Moreover, he was there when Maria bled, and it was useless for him to deny it now, and the prosecutor later charged him with first-degree murder.

We have other forensic evidence, such as glasses left at the scene, analysis of shoe prints on the leather jacket, but the fact that Maria's blood was found on John's shoes is of decisive significance, and it is useless for him to deny it. We believe John broke into the apartment after the three college students left Des Moines.This shows that he had been peeping at a certain place in the apartment for a long time. Maybe he had planned this plan in his heart for a long time, and finally waited for the opportunity. He thought he had a nest now, and he could stay there for three days. . How John lured Laura to the apartment on Wednesday night is unclear, but prosecutors believe he may have made sexual demands on Laura, who she refused.So, in a rage, he picked up the barbell and smashed Laura on the head, killing her. On Thursday night, John lured Maria to the apartment in the same way, only to be rejected again.So he beat Maria to death again. On Friday night, John stole the stereo and TV, and then he decided to destroy any evidence that he had ever lived in the apartment.He lit a cigarette with a match, then dumped gasoline around the apartment.However, he made a mistake. The gasoline made the combustible gas in the air continuously increase, and the burning cigarette caused an explosion. John's glasses were knocked out, his nose was burned, and the smoke and leftover matches were nowhere to be found. The French Open has been back and forth, and the cigarette he smoked not only left precious evidence for us, but also nearly blew himself up. He is human garbage, he has no soul, he has done nothing for society, he only knows how to take from others, he has used others all his life - this is what we heard in court from the prosecutors about John's crimes . In court, it's not just the legal evidence that impresses juries. When John sat in the dock, people saw the tattoo on the corner of his eye.Tattoos are tattoos, which use colored needles to pierce the bottom of the skin to create some patterns or words on the skin.Tattoos represent a person's personality and beliefs, which originated from the custom of tattooing skin and body of primitive tribal peoples all over the world. In the underworld, tear tattoos have a special meaning, it means that this person has killed someone.After this case, John stabbed two black tears in the corner of his right eye, which is very important. It seems that he is not smart, and he went to court with those things stabbed in the corner of his eye, and the jury could see clearly. In court, when I questioned him about the tattoo on the corner of his eye, he said it was in memory of two friends who had just died in a car accident.Obviously, he was lying.The tattoo is just a small circumstantial evidence, which plays a supplementary role in the whole case. In the end, John Maimer was found guilty of two counts of first-degree murder and sentenced to life in prison. When Maria's family was interviewed by reporters, they said that they thanked science for helping the police find the murderer.Maria is an environmentalist and loves science, so I'm sure Maria's family will be very relieved to know that the blood on the shoe and other forensic evidence put the killer in prison. And I am even more convinced that no matter how perfect a crime is, it will leave evidence, and they are waiting for us to find them at the scene. John was given two life sentences, apparently he could only serve one because he only lived once.So, will he continue to serve his sentence after his death?If possible, I think, the prison must be much hotter than the fire he set. Forensic identification knowledge tips: Analysis of blood splatter morphology is an important part of crime scene reconstruction. When blood hits the surface of an object, different shapes will be produced due to the difference in surface structure and adsorption.From the shape of the blood splatter, it is possible to infer the crime process, relevant information of the victim or the suspect, etc. Generally speaking, the blood is spewed out at a rate of 20-30 liters per minute according to the victim's heart rate.If the blood is in the form of a round drop, the victim is at rest; if the blood has a "tail", the victim is being moved; if the blood is jetting, the victim's aorta is damaged.Judging from the blood splash speed, if the blood drips on the ground and forms a round shape, it means that its splash speed is low; if the edge of the blood drop is irregular, there are some scattered tiny spots besides the main blood drop , then this kind of blood is from blows, knife wounds, sticks, hammers, and it is sprayed out at a high speed.