Is a defense lawyer permitted to interview and question prosecution witnesses before the trial?

This can be tricky, but in Michigan, a defense attorney has every right to question a prosecutions witness prior to trial. I often will give the prosecutor notice of who I plan to speak to and the nature of my questioning. The prosecutor also has a right to be present during my questioning. The issue of whether or not a defense laywer can question a witness about there past criminal record depends on your State's Rules of Evidence becaue in Michigan a defense attorney cannot inquire into a persons past criminal history or prior bad acts unless that person was convicted of a crime of theft or dishonesty as it sheds light on the persons credibility. I would speak with your attorney or a defense attorney in your area to determine if your state's rules of evidence will allow such questions to be asked of a witness.