Normally, what attorneys learn from informal investigation need not be shared with the adversary in discovery. The first step in informal investigation is deciding which witnesses to interview. Those witnesses with whom contact requires notice to the opponent should be excluded from an informal investigation. This includes the opposing party, unless he has appeared pro se; the opponent's experts; and employees of the opposing party. Witnesses who might be included in the informal investigation are the opponent's ex-spouse, a disgruntled former employee, neighbors or coworkers who are not close friends with the opponent, and officers ousted from control of a corporate adversary. In contacting witnesses informally, the telephone should be used only to decide what kind of personal meeting would make the person comfortable. No attempt should be made to deceive the witness about the purpose of the meeting. What the attorney or the investigator says to the witness and what the witness says to the investigator can be repeated informally or in court. When the witness states things that are helpful, it is important that the statements be precise and subsequently agreed to by the witness in a signed statement. This is best done through a letter from the attorney to the witness asking the witness to either sign the letter as an accurate statement or make corrections. Witness surveillance should be used only when there is strong evidence that it will yield significant results.