The policies of law enforcement agencies differ, but generally, police are trained to take domestic violence calls seriously and with precaution so officers may arrive to the location of an incident with heightened suspicions and concerns for the safety of themselves and those involved on scene. They will usually separate the parties, ask who was involved, and confirm who called 911. Thereafter, they will try to do a preliminary investigation to determine whether there is probable cause to arrest someone. They can make this determination by gathering statements from witnesses and the alleged victim. Depending on the agency, some officers make it clear that someone is going to jail, even if the alleged victim says he or she does not want to press charges or that everything is fine. If there are injuries alleged, they may take photographs, have the person with injuries evaluated by EMS, or transport such person to the hospital.