It is vital for an investigator to plan and prepare thoroughly before conducting an interview. Failure to plan and prepare will result in a failed interview for a case under investigation. Elaborate and analyzed the planning and preparing stage by comparing with some other countries practices.

The planning and preparation stage of an investigation interview is crucial for its success. This stage involves several steps, including understanding the case, identifying the interviewee, preparing the questions, and setting up the interview environment.

Firstly, understanding the case is the foundation of the interview. The investigator needs to have a thorough understanding of the case, including the events, the people involved, and the evidence collected. This will help the investigator to identify the right person to interview and to prepare the right questions.

Secondly, identifying the interviewee is a critical step. The investigator needs to determine who has the information needed for the case. This could be a witness, a suspect, or a victim. The investigator also needs to consider the person's willingness to cooperate and their credibility.

Thirdly, preparing the questions is a key part of the planning stage. The investigator needs to prepare questions that are clear, concise, and relevant to the case. The questions should be designed to elicit the information needed for the investigation.

Lastly, setting up the interview environment is also important. The investigator needs to ensure that the interviewee feels comfortable and safe. This can help to encourage the interviewee to share information.

Comparing this with practices in other countries, we can see some similarities and differences. For example, in the United Kingdom, the PEACE model is used for planning and conducting interviews. This model emphasizes the importance of planning and preparation, and also includes stages for engaging and explaining, obtaining the account, closure, and evaluation.

In the United States, the Reid technique is commonly used. This technique also emphasizes the importance of planning and preparation, but it also includes stages for behavioral analysis and the use of psychological manipulation to elicit confessions.

In Japan, the interview process is more formal and structured, with a strong emphasis on respect for the interviewee. The planning and preparation stage includes understanding the cultural and social norms, and preparing questions that are respectful and non-confrontational.

In conclusion, the planning and preparation stage is crucial for a successful investigation interview. While the specific practices may vary between countries, the underlying principles of understanding the case, identifying the interviewee, preparing the questions, and setting up the interview environment are universally applicable.