Crime fiction that relies on details, especially forensic evidence, will do something similar. One of my short stories relies on a forensic linguist (see “Letters”). If you, having read crime fiction and having learned all about the importance of details, know of a detail in a case, you can speak up.
Crime stories, true or fictional, can help you be more aware of your surroundings. Be careful. Unfortunately, we have homeless everywhere, and they might be armed. As a patrol officer, I kept my distance, six to 10 feet away. I shouted or used static on my radio to rouse a sleeper. I was struck once by a homeless person. When the incident was over, adrenaline drain kicked in. Lucky for me, I found a chair and sat down.
Note: Dealing with the police can be tough, if it happens, but they might be your lifeline. If you live in the Sacramento area, sign up for safety alerts, as I did, @