Once you have identified DNA evidence, you need to find a way to properly collect it and package it. First, never place any evidence that may contain DNA in plastic bags because plastic will retain moisture that will damage DNA. Items such as masks, eyeglasses, bottles, etc., should be taken as is and placed in a paper bag to be sent for testing. Small items such as hairs should be collected and put in coin envelopes or pharmaceutical folds. Blood, urine, saliva, and samples on steering wheels, etc., can be collected using swabs. If the sample is dry, first moisten the swab with sterile distilled water. Then swab the sample and place the swab in a swab box to dry. Make sure you use a cardboard swab box so the swab can breathe and dry without mold or other problems occurring. Once the swab is in the box, the entire swab box can then be placed in a coin envelope or paper bag. Be sure that you always use brand new, clean bags for all of your DNA evidence. I’ve seen crime scene officers grab whatever is handy for their DNA evidence. While this may be adequate for some evidence, it is never acceptable for DNA evidence, which can so easily be contaminated.

Finally, remember that DNA can be easily damaged even after you have properly collected it and packaged it if you don’t store it properly. Direct sunlight and warm conditions can be harmful to DNA. Therefore, don’t keep DNA evidence in a hot room or a patrol car without air conditioning for any length of time. Keep your evidence in a cool, dry environment, and get it to the lab as quickly as possible.

From: DNA Collection and Packaging by Dick Warrington