Which of the following is NOT a method for reporting a crime using your cell phone?

Writing a letter to the police is not a method for reporting a crime using your cell phone because it involves a more traditional form of communication that does not utilize the capabilities of mobile technology. In contrast, the other options involve immediate and direct ways to report incidents through your cell phone, such as texting, calling, or using an app designed for rapid communication with security personnel. These methods allow for a quicker response and often include the ability to provide real-time information and updates about the situation. In an emergency context, where timely reporting can be critical, utilizing a cell phone's capabilities is essential, making written communication outdated and less effective.