This workbook supplements the Chasing Phones law enforcement training classes presented through the California Peace Officer Standards and Training Institute for Criminal Investigations, the California Narcotic Officers' Association, and the Bay Area Gang Investigator's Association. It is designed to accompany the material covered in training and is not intended as a standalone investigations manual. Subjects included in this workbook correspond to the material presented during training, including: Online phone number lookup services and tools Preservation letters including a sample California law Carrier reports for AT&T, Verizon, Sprint, T-Mobile/MetroPCS, and US Cellular with service of process information, records retention periods, and data collection capabilities Burner phones and Mobile Virtual Network Operators (MVNOs) Apple and Google data collections with sample affidavit and search warrant language Tracing Internet Protocol (IP) addresses Investigating applications Investigating websites with evidentiary screen capture tools, historical website copies, and website trackers A detailed guide to the Open Source Internet Research Tool Evidence preservation using hash verification of digital files Sources of low cost or free training on mobile device forensics, social media investigations, computer forensics, and more