Crime Scene Investigator

by Paul Millen

  This would help me identify, for example, a newly washed kitchen floor, to all intents and purposes spotless, but potentially hiding the latent footwear impressions of the offender. I would issue a gentle restraint to prevent the witness stepping too close until I had fully searched it.

  The victim would often notice something unusual which would require greater thought, so it’s important to listen even to the little asides. On one occasion I heard a cleaner at an office premises say that her washing-up gloves were missing. This prompted me to think that perhaps the offender had not been wearing gloves when they entered and there was a distinct chance of finding their fingerprints, if I looked in the right places. On searching the scene I found a discarded pair of rubber gloves with a torn finger, they didn’t belong to anyone at the scene and so seemed to have been left or, more accurately, swapped by the offender. What I did next was a leap of thought. I sent the torn gloves to the fingerprint lab, asking them to try and develop marks on the inside soft fleece surface. The methods which I had available at the scene were not sufficient to achieve this. The lab developed a full set of ten finger marks using gentian violet staining and the offender was identified by an expert fingerprint officer who searched them. It caused a bit of a stir as no one seemed to recall whether this had ever been successful before, although I’m sure it must have been. Perhaps it was just rare.

  Following my initial evaluation of the scene, and before I undertook a methodical search, I would have to deal with any priorities. This would include any items which would decay or deteriorate due to inclement weather or other factors if I did not immediately address them. This was also a matter of time management. Casts of marks which may take some time to dry would need to be made early so I wasn’t hanging around for them to dry at the end of my examination. To allow me to get on with my job I would encourage the often distressed victim to occupy themselves. ‘How about putting the kettle on?’ I would suggest. This took their mind off things and gave them something practical to do. By the time my examination was finished the tea would probably be cold, but drinking it often allowed me to gather my thoughts and make my notes before I left. It got to the stage where I would burn my mouth whenever I drank hot tea. One old pro of a detective, investigating a burglary in a ‘well-to-do’ premises, when offered a cup of tea remarked that he ‘didn’t drink tea’. Within a minute he was offered whisky in a cut crystal glass. Then offered a cigarette, he stated he ‘didn’t smoke cigarettes’. Within another moment he was standing there with a glass of whisky and a fine cigar. As my tea got cold, I looked on in wonder at his use of words.

  Having dealt with the priorities, I could then make a careful search of the whole scene. Observation is the watch word and a strong lamp a reliable companion.

  The first search is usually one which doesn’t potentially destroy any forms of evidence. These are the non-destructive techniques which don’t swamp further techniques. I would ensure no brushing or the use of powders for developing latent finger or shoe marks for the moment. This would wipe away or cover other delicate items. I would carefully observe, recognise, record and recover fibres, blood or visible fingermarks. Only once this was completed would I examine items with a fine brush and fingerprint powder. This would reveal the latent marks of fingers or shoes.

  Fingermarks can be left in deposits of salt, amino acids and other body secretions and also in contaminants picked up by the hands or on the item on which the finger mark is found. Sometimes they are visible and can be recovered by photography or removing the item. On glossy surfaces, such as paint or glass, even the invisible can be revealed. By gently brushing with a fine powder such as aluminium or carbon, the powder adheres to the secretion deposit or contaminant and reveals the detail of the fingerprint of the donor.

  Shoe marks can be found in any contaminant, from house dust to dried rain water or blood. If they are visible they too can be photographed or lifted. The invisible may be revealed by an oblique light, the dust giving a true impression of the donor shoe pattern. Once visible they can be photographed or lifted using static electricity or soft gel.

  As the scene was searched and items recorded or recovered, my notes would be updated. My contemporaneous notes were a record of what I had observed and the exact measurements of what I had found. My notes would, wherever possible, be accompanied by plans and diagrams. These would be of the whole scene, areas within it or of just individual items. Any photographs would be referred to in the notes to indicate when and where they were taken, and any particular item or area of interest which I wished to highlight would also be noted. I felt strongly that photographs should always be accompanied by notes and diagrams, because without them they meant nothing.

  As I recorded and recovered items I would carefully preserve and package them so that the evidence which they potentially contained would not be destroyed or contaminated and compromised before it was examined at the laboratory.

  My final action at the scene before leaving would be to review. This would be one final check to see that it all made sense to me or would do so once we got some answers back from the lab. Only when I had searched the entire scene and recorded and recovered all the evidence I had found would I consider the scene examination complete. But the investigation was not. That would only just be beginning.

  The end of the scene examination would always raise potential questions in my mind, about where I might find the answers.

  I would need to decide what would happen next, perhaps a search of finger or shoe marks against a database or the development of marks by chemical or other methods.

  What makes an individual a scene investigator rather than a scene examiner is a matter of responsibility and ownership. No one else may care about the potential outcomes of the scene examination. As an investigator I did. I would pursue or ensure others pursued the evidential potential, the answers. I would ensure that other members of the investigative team understood the meaning and potential of the evidence. The goal of solving the crime and bringing those responsible to court is shared by all those who consider themselves to be investigators.

  As a crime scene investigator I attended a lot of crimes, often within a particular area and often over a period of time. So it was quite natural that I would begin to notice patterns, either of offending or in the evidence collected.

  It was generally but wrongly considered that criminals keep to one type of offending and within specific geographical areas. The arrival of the DNA database in the UK in 1995 blew this theory apart. Offenders who had been pigeonholed as burglars or robbers were found to commit other crimes, such as theft by deception or, in some cases, sexual offences, and not only within a local area. The national database was able to link criminal activity over a wide area.

  Intelligence within the crime scene investigation process begins with the soft patterns which the scene investigator notices. This may be a particular footwear mark appearing at a number of scenes, often within a local area over a period of time. The shoe may be known to be a common pattern fashionable at the time but when it is linked with a type of burglary in a particular area, usually at the same time of day and where the same type of goods are stolen, it doesn’t just suggest coincidence.

  At one time I noticed a series of burglaries of a similar nature, and I saw the same shoe pattern originating from the offender. After a period of time I had accumulated enough of the pattern to piece it together and identify what the whole shoe pattern and the upper style looked like. I even managed to instantly notice the mark on a very thin strip of wood on a door jamb which had been kicked in. The mark was in dust and revealed all the damage features within the shoe itself. It was not very common. It bore the name ‘Banana’ on the sole. So I put a few notices around the police station so that police officers could look out for it. Within a few days a police officer called me down to the Charge Room where he had just brought in a young man for another offence. He was wearing shoes of the right pattern. Submission of the shoes and crime scene mar
ks to the laboratory confirmed that in at least one of the scenes these shoes had made the marks which I had found. The pattern and unique damage features were such that no other shoe could have made the same marks.

  Intelligence can build up by linking similar events together and supporting the links with some physical evidence. I held a local database of footwear and also instrument marks recovered from scenes within my area.

  When physical evidence can be categorised it forms a database which can be searched with evidence collected from suspected offenders. The longest to date is the fingerprint system which has been around for over a hundred years. DNA is a relatively new kid on the block but its success has been overwhelming when used as an intelligence database. Anything which leaves a mark or can be analysed and categorised can be put into an intelligence database. But it is just that – an intelligence database. It is not an evidence database. Once a link has been made, then a comparison to the full evidential standards expected must follow. It is an expert, not a database, who gives their opinion, their evidence, on the findings and its relevance.

  Databases can be made of finger, shoe, tool, firearms, tyre and ear marks and of injuries. They can be made from blood grouping and DNA extracted from body fluids found at a crime scene – blood, saliva, semen – and also in hair. Intelligence databases can be made from the manufacturer’s information in matters such as fibres. This may indicate the occurrence of such fibres in the garments of the general population. Car manufacturers keep databases of the types of light fittings their vehicles are equipped with, along with details of primer, undercoat and top coat paint colours. These are used when glass and paint are found at collision scenes. By identifying the glass and paint it may be possible to identify a particular model and the year in which the material originated. Databases also exist within crime labs for prescription medicines and drugs of abuse.

  All this information forms a web of intelligence which has the potential to be searched and cross-referenced. But the information technology systems must allow this information to be shared.

  It is the expert who maintains the databases of DNA and fingerprints so that they, and only they, can access and compare. When they link scenes or suspects, that information is communicated to investigators so they can show the link on their database. Only the link and not the technology on which it is based are communicated.

  Intelligence based on other factors, such as the methods used by offenders, are useful but they cannot become evidence themselves. Similar fact evidence has some value, particularly if it is sufficiently unusual, but it has its pitfalls. It is best if similar fact evidence can be used as a means to find even one piece of strong physical evidence which can link an offender to a substantial offence.

  I attended a series of burglaries in a particular block of flats over a period of some weeks. In each case the two suspects cut the phone wires above the front door before forcing entry. Once inside, they took jewellery and light items. I managed to find some finger marks and they were subsequently identified and found guilty. Two years later a violent rape occurred in the same block of flats. I was not involved in the initial investigation as I was on leave at the time. But when I returned I was naturally interested. A week into the enquiry no suspect had been identified. Although some fingermarks had been found they were not of enough detail to be searched using the available technology at the time. This meant a direct comparison with a named suspect was the only way they were going to be identified. My ears pricked up when I was told that the phone wires had been cut before the front door was forced and the female occupant raped. Remembering the scene two years earlier, I put the names of those offenders forward for comparison. The marks were quickly identified as originating from the suspects and later examination of the body-fluids evidence supported the rape allegation, for which they were later convicted.

  The investigating officer was commended for his investigation but I received no mention. That was normal. I reminded myself that the important thing was that the offenders were caught and quickly. The events did, however, stick in my mind. Later as a manager I always tried to find ways of recognising the good work of committed and hard-working professionals. They may get paid for doing this, but doing well needs recognition, it cost nothing and inspires greater deeds.

  Much later in my career as a manager, I would review all the laboratory submissions where the investigating detective thought the answer wasn’t helpful. This was mainly to see how we could improve performance, perhaps improve our scene investigation and even alter the sorts of questions we posed for the scientists. On many occasions, the officer’s unhappiness was caused by the fact that no evidence was found to link the suspect to the scene or that it actually eliminated them.

  On one occasion I was intrigued by a case. A young man had been seen breaking a large shop window in the high street, but his attempt to remove a television was thwarted by the alarm and the appearance of a resident living above a shop opposite who duly called the police. The suspect ran off, but a young man fitting the offender’s description was stopped in the next street. The police didn’t like the account they got from him and decided to arrest him on suspicion of attempted burglary. Back at the police station the officers seized his clothing and also arranged for a hair combing sample to be taken, to see if there were any fragments of glass in his hair. Samples of glass were obtained from the frame of the window by a scene investigator who promptly attended the scene. Also it was observed, measured and recorded that the break was above head or chest level. This indicated that any glass on the offender would be most likely on head or upper clothing level. There might be glass on the uppers of the footwear but there was no sign that it had been kicked, and any glass found on the soles of the shoe might come from walking past the scene, a common and legitimate defence. The strongest evidence would be if there were small particles of glass on the head and upper clothing of the suspect, indicating that they were within a few metres of the shop window, or similar shop window, when it was broken.

  Glass evidence is not as precise as DNA. Glass is generally classified into types and measured by refractive index (RI). This is the amount that a light beam is deflected when it is passed through it. In most cases it will not link the glass solely to a specific window, more likely to one of that type. That may be a sufficient evidential level. When a person stands in front of a breaking window they will be exposed to a shower of tiny particles. The higher the break and the closer they are to it will determine where these particles land on them. What is equally important is that these small particles of glass will fall off exposed skin within an hour and off most clothing within a few hours, only leaving a few fragments in particularly coarse cloth after a long period of time.

  In this case, the samples were sent off to the lab: the glass control sample for comparison with any fragments found on the hair combing and the clothing of the suspect. The good news was that thirty fragments of glass were found in the hair combing of the suspect (that is difficult to explain in most circumstances) but the bad news was that none matched the control glass from the scene. The officer unhappily dismissed the case and there it would have stayed had I not reviewed it.

  The presence of such a large quantity of fresh glass fragments in the hair of someone tells a recent story. I was about to enlighten the officer about what that story might be. I asked the officer to see if there were any other cases of burglary where a glass window had been broken. There was one. It was right in the next street. It had been reported a day or so after our original crime as the victim had been away. It was investigated by another detective. I suggested that the officer submit the glass samples from that scene to the laboratory, which he duly did. This time the glass matched and the officer’s satisfaction increased. It was raised even more when he went to arrest the young suspect. He found an item of property from this second scene at his address. It seemed that, having committed this offence, the suspect hid the stolen property, returning to it later after his release
for the first offence. This highlighted to the detective the need to review the answers from scene and laboratory investigations, ask what they mean. The answer is the answer, the question may be wrong. So ask another question. This was a lesson the detective learned and I was glad to be a part of his education, as I too had been educated in the past.

  This is an aspect of reconstruction which is useful at the scene, to try and determine an offender’s path or the sequence of events. It equally applies to reviewing what is understood about the crime when further information (such as laboratory results) is available.

  Reviewing an investigation is a rolling process and needs to take place every time an answer comes back from the laboratory. Answers would inspire in me further questions until who, where, when and how was satisfactorily answered.

  It wasn’t all serious stuff though. Even in the darkest of moments there was a black humour which kept me in the real world. Finding the funny side of things would keep me and my colleagues human. So whenever there was tension or horror someone would always remind you of a funny incident. Throughout my career it was always my intention to ensure that I investigated crime without becoming a victim of it. By the very nature of the job I could expect to be present at the aftermath of the most awful crimes. This meant I always had a respect for my own safety.

  The early 1980s on G Division was the time when the Irish Republican Army was at their most active. I often received reminders to check under my marked police van whenever I got into it, in case a bomb had been placed there. I always listened to the advice and checked. One morning I and my SOCO colleagues received another reminder. Mark Russell, one of the team, dismissed the warning as unnecessary worry. A few hours later, having examined a scene, he got back into his van and slammed the door. Immediately there was the mechanical whirring. Panic overcame him and fearing the worst, he jumped out of the van, ran across the road and dived head-first into a bush, with his hands behind his head. Lying there for a moment he realised that the whirring was still with him. Examining his pocket he found his electric shaver. He got up, nonchalantly dusted himself down in front of the viewing crowd and, with as much dignity as he could muster, he got back into his van and drove off.