"photograph. In 2007, the Federal Bureau of Investigation (FBI) developed a software application known as the Evidence Collection Management (ECM) System."
https://www.fletc.gov/sites/default/files/FLETC_Journal-Fall_2016-508_0.pdf
The ECM is a big box, it's the management system for the evidence being collected. It prints evidence tags and takes inputs from cameras on site, etc. On top will also be a big yellow box. In that yellow box are items used to get other evidence, like vials, bags, etc. Everything gets logged into the large box in the bottom which is a computer system. Hence the name ECM-or Evidence Collection and Management. The above article explains the system in more detail.