Chapter 33 third chapter

Now there is another problem that also draws our attention.Robert had a girlfriend, and in this case he still caused the fact that he raped and murdered Don, which revealed a very strong subjective desire.There is also something incredible about this point. Assuming that Robert wants to solve the sexual problem, he can be satisfied with his girlfriend. What's more, he didn't have any unpleasant things with his girlfriend before Tang's case happened. Therefore, Robert did not have the possibility of vicious emotional transfer at that time.But even under this premise, he still chose to rape and kill Tang at three or four o'clock in the morning. It seemed that he knew Tang's exact off-duty time.Tang often arrived home around one o'clock in the middle of the night, and the time between when she went to sleep and when she was brutally murdered was only about three hours.This can at least show that Robert has fully implemented and prepared everything, and is only waiting for the implementation of the plan.This cruel and evil idea had been brewing in his mind for a long time, once he made up his mind to act, a bloody disaster would inevitably happen.

At the same time, we also know that the fingerprints on Robert's file don't have enough ridges to be sure they match the pillowcase, there's no way to compare them. When we appeared in front of Robert again and asked him to cooperate with the investigation.Robert was getting impatient and not working with us the way he used to, even threatening to accuse us of harassing him.It was as if he had changed completely, and he said repeatedly that he never wanted to see us again, that he was innocent. I was prepared for Robert's anxiety, and I also analyzed and investigated, but there was no evidence, and there was no way to arrest him.

I have never encountered this kind of situation in the previous case handling.If it cannot be determined that the fingerprint is Robert's, the defense attorneys will use this to overturn our case against him in court.If that is the case, there will be big troubles, and I am even a little worried about the detection of the case. What do we do if the defense lawyer asks whose fingerprints are these?Shall we say we don't know?If the defense lawyer still asks, are the fingerprints of the murderer?We say no?Or can't be proven to be, so what?My job requires me to answer all questions, and if I don't, the defense attorneys can use that as a reason to terminate the case!

I am relieved that the prosecution decided to take all the eggs in one basket and arrest Robert for murder, but I am also worried, what if the arrest is wrong?I seem to be a little bit tied up in front of the case. The prosecution has their reasons. They hope that the new fingerprint identification technology can confirm that Robert's fingerprints are consistent with those at the crime scene. By this time, I can only have a slight idea of ​​winning for imaging technology instruments.At the same time, I am more meticulous about the work I am responsible for. After Robert was arrested, I watched closely as the technical police took his fingerprints, finger to finger, to make sure that each finger was carefully sampled and that the prints were as clear as possible.The pass rate of fingerprint identification is directly related to the fingerprint pressing method. If the wrong pressing method will not be able to perform effective identification, it will also result in unsuccessful fingerprint identification.

As soon as I see a clear press, I take it back to my office and start checking.When the technical police took Robert’s fingerprints, they first observed the fingerprint core of his finger, and then pressed his fingerprint core to the central depression of the collected object and slowly lowered it, letting the fingertips press on the collected object. things. At the same time, I saw that Robert put his finger in full contact with the fingerprint collection surface as much as possible, pressed slightly harder, and kept the pressing position for about 2 seconds.The technical police kept his fingers from moving, and did not let him lift them until he finished pressing.

After a month of analysis and testing, we finally found the answer.On this day, Tiller, the forensic doctor who was in charge of this fingerprint comparison, called me.He told me that the imprint left on the pillowcase was the fingerprint of his left thumb, which matched the outside of Robert's left thumb.After hearing this, I couldn't restrain the excitement in my heart. This case can finally be truly closed. To be honest, I also spent a lot of time comparing and analyzing the imprints from every angle before I came to the identification conclusion.At the same time, I had another inspector follow me and watch me do everything to make sure I didn't make any mistakes in the identification process.

About fingerprints, I was at a party talking to Thomas and Jim about its origins.The study of fingerprints originally belonged to the scope of biological genetics, and it was also one of the subjects of anthropological research.The earliest person in the world to study fingerprints was Henry Fultz, who was the first to publish the journal "Fingerprints" in the world. He is a famous doctor of biology.Fingerprints are one of the three major objects of skin texture studies. For ordinary people, their understanding of fingerprints is limited to the "pattern shapes" of fingerprints that can be observed by the naked eye, such as bucket shape, skip shape, and arch (bow) shape.

But there is a problem. Image enhancement technology is new and has never been admitted as evidence in court.I was very worried that the evidence we were using might not be accepted in the serious scientific community because it has not yet been recognized as good science. This is the first time anyone has taken this technology and taken it to court where it will be challenged and put to the test.To this end, the court held a hearing to decide whether evidence obtained using this new technology should be admitted. I still remember that at the hearing, I made such an explanation about the image enhancement technology.I said: "The purpose of fingerprint image enhancement is to enhance the contrast of ridges and valleys, so that the image is clearer and more realistic, which facilitates the subsequent extraction of fingerprint feature values ​​and provides a basis for correctness." Then Tiller made a speech to supplement what I said.

I hope that Tiller will continue to speak at the hearing. I think this is an opportunity. It should be said that my intuition told me that I have been looking forward to it for many years. Today, I finally got it.This hearing is very important to solve Tang's case. If today's hearing is unsuccessful, the murderer who killed Tang will be free. Thinking of this, I feel very angry in my heart. Tiller and I, along with Thomas and Jim, had already mastered a lot of image enhancement techniques before.I can imagine how eloquently my partner Tiller will speak about image enhancement technology at the hearing.At the same time, I was also observing the emotions of the opponents. Rare tension and anxiety had even appeared on their faces, which was an effect I hadn't expected in advance.I think the fact that the opposition is so excited shows that they have obviously fallen into a passive position.This effect should be attributed to Tiller, who not only demonstrated his talent at the meeting, but most importantly, since then, similar cases can be solved by this novel method.

At the hearing, I was deeply moved by Tiller's talent for speaking, and I couldn't help but think of the businessman selling image enhancement technology equipment. I searched for him with my eyes, but I found him sitting on the side in front of us. I also found a rare confidence in his eyes, and I had only one thought at the time, as long as the criminals were brought to justice, that would be enough.Of course, I will also be proud and admired by this set of image enhancement technology instruments. The last thing I presented to the hearing was about fingerprint smoothing, which is key in order to get an evenly shaded image.The smoothing process I introduced is to select the pixels of the entire image and the mean square value of its periodic gray scale as a fixed value for processing.

Opponents claim that this is an "unfounded" technology because its "falsification" has altered the image of the fingerprint. Forensic expert Pam Ringer, who sat on the other side of me, explained that the human eye can only distinguish between 16 and 32 shades, while a computer can distinguish 256 shades. Forensic expert Pam Ringer's words caught the opponents by surprise.It is obvious that the opponents have not yet grasped enough reasons to refute us in the application of image enhancement technology.The opposition does not have enough reasons, which means that image enhancement technology will be used in criminal detection. I also introduced the issue of fingerprint binarization at the meeting.I found that the opponents are also insufficiently prepared on this issue. They don't know that the grayscale of each pixel in the original grayscale image is different. During my speech, forensic expert Pam Ringer also kept interjecting. He also has many unique features, which made me feel more confident.Pam Ringer said in a supplementary statement that the image enhancement technology simply removes the pattern of the fabric grain, making the dark parts of the fingerprint darker and the light parts between the ridges lighter. The point is that some of you here have not seen the horror of Tang's corpse. If you have seen it, you can understand why we are so eager to see this new technology be recognized immediately.I said that I spent almost a whole day disposing of the corpse.When I said this, everyone was listening attentively, including the supplier of the imaging enhancement technology.I also found that even the judges listened carefully. I continued around the image enhancement technology, and I said that the enhancement technology does not change the data, what we get is a real photo of the fingerprint.At this time, Pam Linger also said: "The image I took some time ago, I can make it again today. If necessary, I can repeat it 100 times." After hearing her words, the opponent booed slightly, thinking that this was impossible.I had Pam Ringer come up on stage to demonstrate the imaging process and she took out the first pattern and then the fabric image.You can see that the fingerprint hasn't changed, it hasn't moved, its groove lines haven't changed, and I think that's very convincing to the judge in this case. Regarding the fingerprint image thinning process, Pam Ringer said that this is the process of reducing the width of the ridges to the width of a single pixel, and then obtaining the skeleton image of the ridges.This process reduces the amount of image data, makes the ridge shape clearer, and prepares for the future feature value extraction. The judge was thoroughly convinced that the image enhancement technology had altered the bloodstained fingerprint. The court allowed fingerprint evidence to be used in the next trial, which was established as legal precedent and the evidence is valid in this case.The ending I was hoping for was finally here. But a new problem arose, and prosecutors wanted more evidence than fingerprints to present to the court.Robert was charged with the murder of twenty-two-year-old Don, and he should have had the murder weapon, but we didn't find it. This is a fact, we do not deny it.Next, we will look for the criminal's murder weapon.Fortunately, I am not complacent, because my intuition tells me that everything should not be eager for success.But where to find the murder weapon?Not finding the murder weapon still does not convict Robert. To be honest, I am also disturbed that the police did not find the suspect's murder weapon.Recalling that in court, when the fuzzy fingerprints left on the thin pillowcase were finally confirmed as irrefutable evidence, supplementary evidence appeared. It seems that finding this hunting knife is a top priority.Of course, I am still relieved that the court was able to confirm the whole process of the iron evidence, although the problem has not been really resolved. Where is the murder weapon?I kept asking myself again and again, and at the same time, I was constantly asking for the opinions of my colleagues.Everyone fell into heavy thinking again, and the development of the case seemed to be at the end of the mountain.I told my companions that maybe things weren't as bad as we thought. Where is the hunting knife in the hand of the criminal who killed Tang now?In a place like Richmond, with so many rivers, hiding a knife is a breeze. One day, I specially invited several companions to sit in the restaurant where Tang worked.Everyone seems to know my intention of inviting them here. In fact, I did not hide it from them. I said that I invited you here for coffee to pin my hopes on you. I was very disappointed in the result, and everyone was still at a loss. Only investigators Thomas Tiller and Jim Dorton are still repeating the reasoning of the case: "The broken window of Don's room faced the road directly. After committing the crime, the criminal jumped out of the window and took the murder weapon with him .” I seem to have a premonition of something.I said that while we are doing this kind of investigation, the public prosecutor will also be doing the same work as us, and we are not alone. In retrospect, it seemed like fate at the time, when the suspect's murder weapon was found six months after Don's murder.In the room where Robert used to live, a maintenance worker found a hunting knife behind the passage board in the bedroom. When I got the call I was thinking maybe there was something wrong with Robert's house and the maintenance guy removed the access panel and when they looked inside they found the hunting knife wrapped in a sheet. In the criminal investigation laboratory, we did a simple test to determine whether it was the murder weapon.A photographic overlay technique was used to contrast the pattern of the hunting knife with the impression of the knife on Don Bruce's pillowcase. I know that the extraction of traces in site surveys first requires photography.On transparent flat glass, double-sided overlapping fingerprints are a common trace. The lines on both sides affect each other. It is difficult to take pictures that can be compared with ordinary methods. The general method is to first stick one side of the fingerprint with adhesive tape. Then take the other side, which can easily cause damage to fingerprints.Therefore often need to utilize optical method to extract fingerprint. The result of the comparison is that they are exactly the same.This is undoubtedly good news for us, and I said to Don in my heart: "Poor girl, you can rest in peace now!" Then, the last piece of evidence the police provided was a DNA test on the semen found at the crime scene, which also proved to be an exact match to Robert's DNA. Prosecutors believe the victim, Don Bruce, went straight to bed after returning home from get off work at about one o'clock in the morning.The house she lives in has two floors.At about four o'clock in the morning, Robert pried open the front window of Don's room on the ground floor and crept upstairs.He stabbed Don in the heart, then raped her as Don slowly bled to death. Here, I couldn't help but once again had the idea of ​​tracing the root of Robert's abnormal psychology. What is the reason that prompted him to take such a risk?Could it be that it was just a difference of thought? At the crime scene, Robert made the fatal mistake of wiping the knife on the pillowcase, leaving an indentation of the murder weapon, which was in the same shape as the knife later found in his room.He also left a bloody partial fingerprint on the pillowcase, which became evidence of his subsequent murder. In the face of the mountain of irrefutable evidence, Robert could not deny it. In order to avoid being sentenced to death, he took the initiative to plead guilty.In the end, this vicious gangster was sentenced to life imprisonment. Robert took the initiative to plead guilty to the law. Could it be that his spiritual consciousness has become sober again?I have no idea.But I am very disappointed that Robert was not sentenced to death, and I think he deserved it.In the detection process of this case, forensic science played an important role.In some cases, there is no evidence, and the trial is conducted only by confrontation in court. However, if no criminal investigation evidence is found at the crime scene, the case will be closed like other similar cases.Thinking of this, I couldn't help but think of the supplier of the imaging enhancement technology. If it weren't for his appearance, Tang's case might have disappeared. But I still want to express my admiration to the public prosecution. If the public prosecution did not have the courage to arrest Robert for murder, then the result is not what it is now. At the time of Robert's arrest, we had only circumstantial evidence.But it is the most well-documented criminal case in my 24-year career. The only thing I can't get over is that Robert doesn't deserve to live in this world. He doesn't deserve to breathe, eat, sleep, laugh, and every bit of life that he doesn't deserve. How many years have passed, and I still remember the case of Don still vividly, because Don was only twenty-two years old when he was killed.The thought of a vibrant flower just wilting just like that is keeping me up at night because I have a daughter too.I sometimes get speechless when I see her because I love my daughter so much. So, isn't Don also my daughter?I have thought so more than once.