You don't give any details of your situation. However, if you were not under arrest at at the time that you spoke with the investigator, then anything you said can later be used against you in any criminal proceedings. The fact is that a person is under no obligation to speak with the authorities, even of they come to your home. They are trained in getting people to make incriminating statements about themselves (or others). That's why you should never submit to any questioning without the presence of legal counsel. At this point, you should speak to an attorney about the specifics of your situation; they can best advise you further. At until you obtain an attorney, do not speak with the investigator again.