Updated: Aug 20, 2018
If you believe you are suspect of a crime or legal issue...
If you believe you are being investigated for a crime - you should call an attorney immediately. You should not talk to the police without first consulting an attorney. If you are contacted by an officer - always be polite. You do not have to answer questions, but you do need to politely request to please call an attorney. How you act can be very important - both because of the impression you make on the officer and how a prosecutor, judge or jury relates to you later.
Sometimes an attorney can help gather evidence that helps persuade an investigating officer or prosecutor evaluating a case that there is no case worth pursuing. Most cases are investigated by a police officer who then sends their report to the prosecutor's office for review. Some prosecutors just review police reports and make filing decisions, so getting evidence in early is important. The prosecutor can add or delete charges suggested by the arresting/investigating officer - or decide not to file any charges.