Cui Daozhi, A Forensic Legend

Feng Rui

In May 1955， Cui Daozhi was transferred from military service to the Heilongjiang Provincial Public Security Department， where he began his 66-year career as China's first-generation of forensic police officers.

At present， the 87-year-old police officer has become a well-known expert in trace evidence examination and a treasured role model in China's criminal investigation system. He was appointed one of the first experts in this field by the Ministry of Public Security （hereafter referred to as MPS） in 1999 and awarded for his outstanding contributions to technological advancement in 2006. In addition， he has helped conclude a number of major cases in recent years， including the Baiyin serial rape and murder cases in Gansu Province， the major serial robbery and murder cases committed by Zhang Jun， and the shooting and robbery on soldiers and police officers perpetrated by Bai Baoshan.

Cui's main research topic is trace evidence examination on crime scenes ranging from footprints and fingerprints to firearms， bullet shells and various ballistic marks . He has identified over 7，000 pieces of trace evidence in his career with zero mistakes. His identifications usually hold the key to many hard and cold cases.

Breakthroughs

The samples and materials sent to Cui are usually the hardest nuts to crack， thwarting many other experts' efforts. The Bai Baoshan serial murder and robbery cases were of great importance in China's forensic history. At the height of case-handling， Cui， who had retired， answered the call of the MPS and went to Urumqi to give assistance. He spent a sleepless night and found a decisive factor to end the case.

Bai Baoshan murdered 15 soldiers， police officers and civilians and robbed a total of 1.4 million yuan in Beijing， Xinjiang and other places between March 1996 and August 1997. The serial cases were listed as Case No. 1 in 1996 and the first of the top ten cases in 1997 by the MPS， and the world's third most serious case in 1997 by the INTERPOL. At the beginning of investigation， the cases that occurred in Beijing were identified as being committed by the same perpetrator and so were the cases in Xinjiang. However， a problem arose： could the cases in the two places have been committed by the same person？ Preliminary investigation results showed that the weapon used in Beijing was a Type 81 rifle while the one in Xinjiang was a Type 56.

Actually， before Cui handled the cases， Bai Baoshan hadn't been listed as a suspect in the investigation.

Two different weapons in two places， it seemed impossible to put the cases together！

At that moment， the MPS dispatched Cui to Urumqi to investigate whether those cases were committed with the same rifle. Cui spent a whole night studying the cases and reached a conclusion： the bullet heads and shells in the three cases in Xinjing were fired from the same Type 81 instead of a Type 56. The weapon was used both in Xinjiang and in Beijing on December 16， 1996.

On the basis of his findings， the MPS presumed that the criminal would have been sent to Xinjiang after committing crimes in Beijing. This judgment finally led to the investigation and arrest of Bai Baoshan， the real murderer.

Recently， a deformed fingerprint was sent to Cui for identification. Cui， at 87， still worked tirelessly for nine straight days and nights and identified eight characteristics of evidence that proved to be solid evidence for conviction.

Over the past decades， Cui has put equal emphasis on handling complex cases and academic research， making fruitful achievements in both practice and theory. At the MPS's working conference on forensic science and technology in Zhengzhou in 1975， Cui and his colleagues from four provinces were assigned a research project： The Correlation Between the Length and Width of Palms and One's Height， Age and Stature. With four years of tireless efforts， they collected 125，000 sets of fingerprints from 12，500 individuals. Cui applied mathematical statistics in the research to figure out the normal range of palm characteristics among Chinese people and their correlation with height， age and statures for the first time. The research is conducive to identifying the criminals'physiological characteristics via their prints of hands left on crime scenes.

Cui has written papers on firearm and bullet marks， such as Identifying Pistol Categories According to 7.62mm Bullet Shell Marks， as well as Research on Mark Displacements of Type 64 Pistol Loaded Chamber Indicator and the Type 59 Pistol Ejector since 1981. He also broke new ground in settling cases by establishing identification standards for nail and teeth marks.

In early 1994， Cui found during on-site inspections that some trace evidence left on crime scenes were often neglected because they didn't have strong characteristics. He was deeply concerned that as long as these problems remained unsolved， he would fail in performing his duty. Therefore， he decided to develop a trace image processing system with approval from the Science and Technology Department of the MPS. In order to meet the technical standards， his research group ran thousands of evidence tests and received certification from the MPS in October 1996.

This project realized digital examination of trace evidence from overall images as well as microscopic features. The system was used in on-site photographing and trace examination， playing a pioneering role in Heilongjiang and some other provinces.

Decisive Blows

On October 21， 1994， the General Manager of the Shandong Provincial Rural Economic Development Center surnamed Wang and his wife were shot dead at home. Two 7.65mm bullets were found on the crime scene. Seven years later， the Shandong police identified the major suspect Zhang Changwen and seized a Browning pistol made in Belgium. The Shandong Public Security Department and the Second Research Institute Affiliated to the MPS examined the pistol and deemed that the barrel was abraded so badly that it was unidentifiable. So it was sent to Cui for further examination. He used the "aluminum foil tape" and "bullet trace flattening device" tools and methods he had developed to flatten and join the rifling traces， and concluded that the bullets were fired by the Browning seized from Zhang. On the basis of his conclusion， the case was soon settled. The truth emerged that Wang reported the financial crimes committed by the then-director of the Shandong Provincial Water Resources Department， who hired Zhang to kill the Wangs.

The "aluminum foil tape" and the "bullet trace flattening device" are great inventions developed by Cui.

In 1995， the number of gun-related crimes in China was on the rise. 62-year-old Cui， though retired， had always been closely following China's technological development in bullet trace studies. In 1997， he attended an international exhibition on criminal investigation equipment organized by the MPS. When he saw the automatic system for identifying bullet traces set up by Canada and the US， he was determined to make a breakthrough for China in this field.

He visited seven schools of higher learning and three institutes of precision instruments for the latest technologies to make copies of rifling; he went to the top three aluminum plants and aluminum foil plants in China to develop a high-precision mold; he made four design sketches and worked with four mechanical processing plants to invent an ideal bullet trace flattening device. Through five years of hard work， he eventually mastered the technique to copy rifling from bullet traces by the special-purpose aluminum foil tapes he invented and received a patent accordingly. He was also granted the utility model patent for developing the bullet trace flattening device. Rifling copied by this device is clear and consistent. With his two inventions， Cui and Wang Zhiqiang from the MPS's Material Evidence Identification Center co-developed the Automatic System for Identifying Rifling Traces， which won the certification from the MPS on October 16， 2001. "Developed with strong technological inputs， the system is very innovative， practicable and operable. It works stably without manual intervention and performs better than its counterparts developed by other countries in terms of the speed of data recording and accuracy. The system meets the international standard."

One night in 2013， a gunshot case took place under an overpass in Jimei District， Xiamen. The bullet head was found in the body while the shell was missing， presumably stuck in the gun.

No evidence was left on the crime scene other than a bullet head and a corpse.

When the case got solved， the murder suspect was apprehended and his gun seized. The shell remained inside. But the barrel was so worn that the police failed to identify its relation with the bullet head. The suspect refused to admit the crime. So the only way to put the perpetrator to justice was to prove that the bullet head was fired from that gun. The tough problem had frustrated all efforts.

When difficulties occurred in bullet investigation， police officers across China would turn to Cui for help. So did the Xiamen police： we've tried our best anyway and there is nothing else we could do. In our last resort， let's go to Heilongjiang and consult Cui！

So they visited Cui. He took the gun， bullet shell and head to his laboratory immediately， examined them with his devices， and confirmed that bullet head was shot from the gun with ample evidence.

To train the younger generation of police officers， Cui， in his 80s， continued to tutor with meticulous effort. But when it came to the key procedures such as photographing and evidence collecting， he would always do it all by himself. Many doubted whether his approaches would work when dealing with the Xiamen case. But when Cui provided solid evidence， everybody was convinced. His conclusions and photographed evidence were so clear that even the general public could understand them easily.

Family Traditions

At the age of 84， Cui received a mission from the MPS to investigate a complex case in Shenzhen. It was the most challenging one for him throughout his career because he got injured on the very first day of the mission. His left eyeball was hit by an iron clip attached to his backpack strap which broke suddenly， causing an L-shaped wound on his eyeball. As he had a cataract on the other eye， the wounded one caused severe pain and a big trouble for him. But he kept on working for three days and nights and would only take a nap when getting tired. His third son Cui Yingbin visited him and found that his father had contracted conjunctival hyperemia after working for so long. When the son lifted Cui's eyelid and saw the wound， he couldn't help but shed tears. So Cui was taken to the Harbin Ophthalmology Clinic instantly for treatment by his son and got four stitches in the eye.

Even under such difficult circumstances， Cui fulfilled the MPS's task with high standards and compiled his cases onto PPT slides for educational purposes. Meanwhile， he was also working on creating records for non-standard firearms.

Cui's industrious work style has exerted impact on his family. He practices strict self-discipline and also has high expectations for his three sons. As a result， his youngest son Cui Yingbin has followed in his footsteps in trace evidence examination at the Harbin Public Security Bureau. His oldest son Cui Chengbin is a technical expert in the criminal investigation unit of a provincial public security department. His second son is a key member of the anti-cult unit of a provincial public security department. It's respectable that Cui could maintain his work for over 60 years. Even at the age of 82， he rushed to Gansu by train to tackle the cases in Baiyin at the most critical moment.

"Almost on every mission， Cui never flies if there is enough time， because he wants to save expenses，" said Liu Jia， a division chief of the MPS Criminal Investigation Department. She added， "He never takes a car to the train station or airport. Instead， he always takes bus or metro by himself."

Cui's reputation has spread from Heilongjiang to the whole country. Although he has many touching stories and outstanding achievements， he never grows complacent： "If I have achieved anything over these years， it should be attributed to the Communist Party of China. It is the Party that gives me a stage to fulfill myself and I've always wanted to pay it back."

Pragmatism

Cui always says， "We must practice pragmatism in whatever we do."

Indeed， that's not easy！ Cui refrains from talking big or delivering exaggerated information. Now he is busy compiling textbooks and preparing for courseware concerning bullet trace examination for the reference of the younger police officers.

No matter what judgments he made， he would make them as professional as possible. Once adopted， they should be flawless.

Cui was re-employed by the Criminal Investigation Unit of the Heilongjiang Public Security Department after retirement. The Unit adopted a new fingerprint recognition system in 1999. Many younger police officers majoring in computer sciences had limited knowledge of fingerprint recognition. Cui， who was already 65， turned out to be their teacher.

Cui has developed various coursewares for others to learn， but he could not give lectures， as he was always traveling for work. He also designed examination papers that were beautifully illustrated. Hearing his stories， a number of green hands in this field across Heilongjiang came to him for instructions. Even as their questions varied a lot， Cui would answer them all. Be it an easy or hard question， he would explain it carefully until they could comprehend it. In conclusion， Cui always shared what he mastered without reserve to anyone who wanted to learn. Sometimes he even gave his cell phone number in case they didn't understand. Of course， he would answer each phone call when he was available. Cui also played a decisive role in developing the fingerprint database in Heilongjiang Province， which helped to solve many cases after being adopted that year. The exam papers that he designed are still kept by many police officers.

At the end of 2016， the Heilongjiang criminal investigation authority launched a province-wide campaign to compare the fingerprints concerning long-pending murder cases. The task force assigned Cui with over 70 cases， hoping that he could have a browse when he was available. However， he finished them all in three days consecutively， marked each of the fingerprints in red by image processing software， and gave explicit instructions. Hence， many long-pending cases were concluded with his assistance.

（Translated by Agnes）