In Search of Admissible Evidence

By using criminal investigation technology as a secret weapon， this person not only makes the deceased "open up" to reveal their grievances， but also is able to trace the real criminals to their hiding places so that they have nowhere to hide. He is the expert who specializes in offering technical support and providing crucial evidence to the investigation and prosecution concerning a large number of major criminal cases. His name is Bai Yongqiang， the deputy director of the Criminal Technology Division of the Criminal Investigation Department in the Yinchuan City Public Security Bureau， Ningxia Hui Autonomous Region.

"Lao （Old） Bai" is not Old

"'Lao Bai' likes to get to the bottom of things. His world is full of question marks！" This is Bai's colleagues' impression of him.

"Lao Bai"， as his colleagues usually refer to him， was born in the 1980s. However， because he is a leading expert in DNA technology in the Public Security Bureau， and has been engaged in the field of criminal technology for 12 years long ， people prefer to call him the affectionate honorific "Lao Bai".

But few of his colleagues knew that in 2010， when Bai， a competent doctor who had previously practiced clinical medicine for nine years， chose to change his career to become a police officer， he encountered this kind of first "question mark" in his life.

"Only a week ago， I faced patients full of life; but a week later， what I was facing were all cold corpses. This tremendous mental contrast was really a challenge for me！" The memory of his first appearance at the crime scene as a forensic doctor is still fresh to him up to this day. It happened in January 2011， when he had just reported for duty at the Criminal Investigation Department. On that day， he arrived at the crime scene to investigate a fall accident in a high-rise building. "In the past， I brought a stethoscope with me wherever I was going， but now I'm carrying a brief case for investigation. In the past， I used to practice traditional Chinese medicine with my professional examining skills such as perceiving， listening， asking， and checking the pulse for my patients， while nowadays my eyes are full of blood stains and mangled bodies. I'm really amazed！" This confusion made the always self-assured Bai doubt about himself. "Can I manage it？"

Bai was affirmative： "Certainly I can！" In the following weeks and months， in the daytime， he would work closely with the experienced forensic doctors and visit crime scenes or conduct autopsies. And at night， he would be absorbed in his old academic textbooks at home to increase his professional knowledge in this area. He also had the habit of examining crime scene photos on file in order to learn more from them. Besides making great efforts to improve his photography skills， he also spent much time enhancing his psychological resilience in tough situations at work. Soon after， "Lao Bai" acquired the credentials to handle cases independently and the authority to issue official medical examination reports. His perseverance and determination in "cracking a hard nut" earned him general approval. Not long after this， he was assigned the job of establishing a DNA testing center in the Yinchuan City Public Security Bureau. With the experience of introducing new equipment to this project and the previous practice of working and learning with his colleagues in the Ministry of Public Security and the Public Security Department， "Lao Bai" gradually obtained a certain level of confidence， albeit occasional doubts from colleagues.

"Is it feasible to rely on a six-month-old laboratory  to investigate and solve major criminal cases？"

"There is no room for errors in evidence examination. As to the reliability of this technology， if it fails him because of its deficiency， the negative influence on the result of solving a crime will be irreversible. Can we really count on this young man in his early 30s to do all this？"

To this kind of questioning， his answer was affirmative： "Sure， I can！"

In March 2012， a homicide occurred in Lijinghu Park， Xingqing District， Yinchuan City. After a tremendous amount of effort overnight at the crime scene， Bai eventually extracted from the victim's backpack some key evidence that might have been left by the suspect. But the doubting voice emerged again among his colleagues： "For this minimum amount of trace evidence， there is only one chance to test it. And the result was crucial as to whether the case could be solved successfully. Should we send the evidence back to the Ministry of Public Security for testing， or should we have it tested here in our DNA laboratory？"

"Lao Bai"， as the founder of this laboratory， was quite enthusiastic， "Let me give it a try！" He was resourceful in accomplishing this mission. Seeing that the automation level of the equipment was not sufficient for this test， he ran the equipment manually. Realizing that the technology he was relying on was still not fully developed， he chose to stay and keep a watchful eye on the ongoing process. Fearing that any imprecise outcome might occur， he took out all the samples and scrutinized them one by one without exception. In this way， "Lao Bai" stayed in the laboratory for a whole 72 hours. When he at last obtained the matching sample， the whole task force let out a cheer and felt greatly encouraged. With the physical evidence provided by Bai， criminal investigators eventually captured the suspect successfully.

"For me， this is not only a settlement of a case but an encouragement as well. It tells us that， for any future cases with similar characteristics， the Yinchuan Public Security Bureau has obtained the capacity to examine the evidence independently！" This experience still stirs in him strong feelings up to this day.

Making Evidence "Talk"

According to Bai， evidence testing in the DNA testing center turned onto the "highway" after this experiment. Accordingly， he and his forensic colleagues started to get involved in almost all the major thorny criminal cases in the city. To solve those cases， people relied heavily on the physical evidence they provided. In the same period， with the skills and expertise gained from the practice and experience of handling more cases， the laboratory's biological testing technology was becoming more and more mature. As "Lao Bai" recalled， in 2017 alone， he and his team provided technical support for the investigation of more than 4，000 cases in the city and tested more than 22，000 biological specimens. He admitted that the job was very tough for him to handle sometimes. However， whenever a new case came， he would work on it without sleep for days， till the test results came out and were passed over to the investigators and task forces without delay. And then he would take a nap while sitting at his table. But he said he was quite contented and very proud of himself seeing so many cases solved because of his tireless efforts.