 Careful, darling. Policemen arrive, planes outside the house. The other protects the crime scene until the detectives get there. The officer in charge plans the search and makes the assignments. When physical evidence is found, it is immediately photographed. The picture includes a ruler for scale and an identifying caption. The officer in charge places it in the crime scene sketch he had made at the start of the search. Burglary is a secretive crime. That is why physical evidence is so important to its solution. Even the eyewitness can contribute little. Well, never even got a look at it. Is this the robe you were wearing when you were attacked? Yes, sir. That's it. We'd like to take this back with us for laboratory examination. It is the most important clue in this investigation. But only if it reaches a laboratory properly identified, preserved, packed, and accompanied by a letter of transmittal. The FBI laboratory has extensive facilities and expert examiners available free of charge to any law enforcement agency. But whether evidence is sent to them or to a local laboratory, the same procedure should be followed. They are described in the FBI pamphlet, suggestions for handling of physical evidence. One section covers in general the proper ceiling of evidence for shipment. This is essential if the evidential chain is to be maintained. Then should be double-wrapped and sealed. A transmittal letter should be sealed in an envelope marked invoice and affixed to the inner seal box. Through a transmittal, it should include the full names of subject and victim, the offense, date, and place where it occurred, and other circumstances of the case. Individually list the items being shipped and the information desired from examination or analysis. These are some general principles to be used in packing and transmitting any physical evidence to any laboratory for examination. Each kind of evidence, of course, presents its own special problems of identification, preservation, and shipment. Some of these problems are also covered in the pamphlet. Many more are a matter of understanding how to safeguard the evidential chain and the requirements and techniques of the forensic laboratory. During the course of the burglary investigation now in progress, you will learn something about each of these subjects. After each piece of evidence found at the crime scene is properly collected and identified, we will move forward in time so that FBI experts will tell you what can be learned from this evidence through laboratory examination. The crime scene has been thoroughly but vainly dusted for fingerprints. Obviously, the burglar wore gloves. Yet it may be worthwhile to send anything portable related to the crime to the laboratory for further examination. The flashlight left behind by the burglar is identified by the investigator who scribes his initials on it. The officer in charge is a witness. He makes notes on circumstances and location of the evidence. Each piece of evidence must be separately packaged and labeled before being included in the shipment to the laboratory. A well-stocked crime scene kit is invaluable for keeping on hand a wide variety of packing and marking materials, as well as other equipment the investigator may require. The FBI identification division's latent fingerprints section. Experts have examined the evidence sent in from the crime scene for latent prints. The flashlight was dismantled and all parts were examined and processed. The only identifiable latent prints were developed on the batteries. Fragments, Harry, these prints if identified will disclose beyond any doubt who touched these batteries. Identification may be affected through comparison with the prints of named suspects or through search and comparison of prints of known burglars. Finger prints provide a positive means of personal identification and form an indisputable link in the chain of evidence. The prints on the batteries of the flashlight establish the suspect is having touched them at some time. However, it may take additional evidence to place him at or near the crime scene. Several latent prints were developed on the batteries. Here is an enlargement of one. The drape that concealed the assailant may have hair or clothing fibers adhering to it. Wrapping paper is spread to preserve any that are dislodged and then used to pack the drape for shipment to the laboratory. Investigators initial the lining to preserve the evidential chain. In crimes of violence involving bodily contact there is often an interchange of hairs and fibers between the victim and the assailant. The hairs and fibers unit of the FBI laboratory searches for, examines and compares such evidence. This bathrobe worn by the victim is first searched for obvious hairs or fibers adhering to it. The garment is then scraped to dislodge any other particles. From a microscopic examination of hairs we can determine race, body area, any type of artificial treatment and damage to the hairs such as crushing. Hairs recovered from the victim's garment can be compared with hairs from a suspect. The drape which concealed the assailant will be searched for both hairs and fibers that might have adhered. Now for our examination to provide effective evidence it is absolutely necessary that each item be handled carefully to prevent loss of any hairs and fibers wrapped separately to avoid contamination and properly marked for later identification. This bathrobe worn by the victim has stains. When the examination for hairs and fibers is completed the garment will be sent to the serology unit of the FBI laboratory for examination of these stains. Blood stains found on the carpet may have also been left by the burglar. After they have been allowed to dry the investigators collect as much as possible of the powdered scrapings. The pill box containers have tight fitting lids. They are marked with initials and date and will be sealed before shipment to the laboratory. Samples of unstained carpet nap will also be sent for control purposes. This is the serology unit of the FBI laboratory where it is our responsibility to identify stains that are made for the various body fluids. Blood, seminal fluid, saliva and urine. In this case, the stains on the bathrobe and the scrapings from the rug will be subjected to certain tests. First of all, to determine if the stains are blood and thereafter to determine if they are human or animal. If the blood is human, the blood group will be determined. Adequate controls are run on the unstained portion of the cloth in order to ensure that the results we are getting are coming from the blood stains. While a blood grouping alone is not sufficient to identify a person, it does lend weight to an identification and it may well be sufficient to eliminate a suspect. It is important to remember that blood stains should be thoroughly dried before packaging for shipment to the FBI laboratory. This will prevent putrefaction. After drying, articles should be packaged separately. Scrapings of blood should be placed in a container with a tight fitting lid in order to avoid leakage. Liquid blood specimens should be forwarded to the FBI laboratory, air mail special delivery as soon as they are received from the medical examiner. Exterior surroundings have been as carefully protected and thoroughly searched as the interior crime scene. A shoe print is photographed. It may prove to be that of the escaping burglar. Later, a plaster cast of it will be made for comparison with any suspect shoe print. When this door was forced by the burglar, marks were left on the wooden door jam and the metal striker plate of the lock. Marks on the door have been photographed. Now the investigator removes the striker plate and marks it with his initials before sending it to the laboratory. The officer in charge witnesses this and covers any additional data in his notes. The tool marks unit of the FBI laboratory. Our examinations concern the identification of tool marks as having been made by a specific tool. They also include the identification of two objects having been originally joined, such as the broken blade of a knife. In this instance, tool marks on a striker plate are being compared with a screwdriver to determine whether the marks were produced by this screwdriver with exclusion of all other such tools. The examination is conducted by comparing the marks on the striker plate with the test marks made by a suspect screwdriver. Tool mark identifications are similar to the identification of a bullet which has been marked by the barrel of a gun. In both cases, a comparison microscope is used. The plaster cast of the footprint was poured and allowed to harden. While it was still wet, both investigators marked the top with date and initials. It is lifted carefully together with any dirt that may adhere to it. Plaster casts are fragile and must be protected with packing before being moved from the site and shipped to the laboratory. This is the tire and shoe print unit of the document section of the FBI laboratory. One way of doing shoe print examinations is to make ink compressions of a suspect shoe which can be compared with shoe prints found at the crime scene. We also examine tire prints, comparing casts made at the crime scene with tires found on a suspect's car. Tire wear may often produce individual markings which are identifiable. This shoe print cast was made at the crime scene. Only loose material was removed to avoid damaging surface detail. It appears to have been handled carefully and was identified by date and initials by investigating officers. It was properly packaged and separately wrapped to keep any dampness from other evidence. It appears to be in good condition for comparison purposes. The glass fragments on the floor may have been smashed by the burglar during the struggle or during his escape. He uses a carton from the ever ready crime scene kit and marks the top with his initials and the date. A second investigator also initials the box top so that he too can testify to the finding of the evidence. The examination of glass is one of the major functions of the soils and minerals unit of the FBI laboratory. Glass from different sources varies considerably. Even two window panes from the same location can be separately identified if they came from different batches of the same glass factory. With these instruments, we can make precise measurements of the amber glass found at the crime scene and compare this evidence with tiny pieces of glass found embedded in the rubber soles of a suspect's shoes. The optical and physical properties match, providing circumstantial evidence that the suspect was at the crime scene. However, the unusual characteristics of this glass and the metal in its applied decorations indicate that further compositional analysis should be made. The facilities we have available for this purpose include the emission spectrograph, the mass spectrograph, capable of an extremely sensitive survey of the elements in the specimen, and the use of nuclear reactors of various types with the subsequent neutron activation analysis being performed by the FBI laboratory. You have seen the processes by which the physical evidence of the crime scene of a burglary and assault were collected, identified, and prepared for shipment to a laboratory. You have heard experts from the FBI laboratory describe to you what can be expected from analysis of this evidence. You have learned that laboratory findings and criminal cases are based upon the comparison of known with questioned evidence and that they may prove innocence as well as guilt. And you have been told of the importance of safeguarding the evidential chain from collection through laboratory examination to submission at the trial. When I arrived at the crime scene as officer in charge of the investigation, I found that it had been properly protected by our uniform men who had responded to Mrs. Wilson's call. I immediately planned the crime scene search and gave assignments to the men working the case with me. I made an initial sketch of the crime scene and filled in the location and description of all physical evidence discovered during the search. Every item found was photographed in place before collection. Anything in the crime scene which might possibly yield evidence was carefully collected. Every item was dated and initialed by the two of us, if possible on the object itself, if not on the containers which were sealed before shipment. Most items were packaged separately on the scene. This was done to avoid contamination or damage. All of the packaged material collected was maintained in my custody and shipped to the laboratory by registered mail to provide a valid receipt. It has remained in my custody since its return to preserve the evidential chain. No further questions.