You are the computer forensic investigator on duty and are called to process this case. List the general steps and tools required to begin investigation.

Problem Description

During a criminal case investigation, a computer was taken as part of the evidence. The computer was found with a flash drive connected to one of the USB ports. It is suspected that this flash drive contains image files relevant to the case. Preliminary investigation revealed that the owner of the computer had the chance to delete some of image files. Other files were renamed so that they do not look like image files. It is also suspected that steganography was used with some of the files to conceal important information. The passphrase used for this purpose is hidden in the device slack space.

You are the computer forensic investigator on duty and are called to process this case. List the general steps and tools required to begin investigation. In addition, because it is a high level profile case, processes must be carefully documented.