You posted this question in the DUI section, so I will assume you're asking about a felony DUI situation, but my answer will apply to other cases as well.
In some cases, a pre-plea report may be useful in resolving a case. The probation department will prepare a report that compiles the defendant's history, both family and criminal, summarizes the facts of the case, includes statements from interested parties (the prosecutor, lead investigator, defense attorney) as well as from the defendant should he choose to discuss the facts. The defense can also submit character letters and references for inclusion.
Why would a defendant participate? If the defendant had already given a statement to law enforcement about their participation in the incident (and assuming it's admissible), then discussing the situation with probation may be beneficial to try and explain, demonstrate remorse, etc. The defendant can also express their willingness to comply with whatever terms of probation are imposed.
If there's still a chance the case will proceed to trial and the defendant's attorney chooses for tactical reasons for their client not to give a statement about the facts, the defendant can still discuss their social history and other factors to be considered.
The probation department will then issue their recommendation. The judge is free to follow or disregard it. They will suggest the threshold issue - whether the defendant is a suitable candidate for probation or not. If they are suitable, the report will often suggest appropriate terms of probation. If they are not suitable, they will spell out the reasons why. Then there's the third type of case - one where on the face of the charges, the defendant is not eligible for probation, although suitable. There, if an allegation can be stricken by the court in in a plea, the probation department may indicate that based on the allegations, the defendant is not eligible, but is suitable. Then, they will indicate that should the defendant be granted probation, certain suggested probation terms are warranted.
Hope this helps.
To add to Mr. Dane's excellent summary:
A pre-plea report (under PC 1203.7) can be a very useful tool for the defendant if, 1) you are in a court where the Probation Department does more than just run the rap sheet and summarize the police report; and 2) if the defense lawyer works it up.
As Mr. Dane indicates, this is an opportunity to get materials in front of the judge and the prosecutor which may lead to a negotiated dispositin of the case. So, it is critical if you are going to do it that you do it well.
First, if we are going to ask that the case be referred for a report, we always put together a mitigation package for the Probation Officer. We have our investigator interview people who know the clinet and we collect supportive letters. The letters have to be of substance and tell the story of the client -- mere reference letters do not help. In addition, we gather anything else that maight be of help -- sometimes medical records, employment records, military records, even pictures, certificates or anything else that helps humanize the cleint and put his conduct in perspective.
Second, we always attend the Probation interview. We prep the client, especially as to whether he or she is going to discuss the facts fo the case -- usually not in a pre-plea. Then we make sure that the officer doing the interview understands our parameters (if any). During the interview, we let the officer do her or his thing but, almost invariably, there is an opportunity to clear something up or to offer to provide additional information.
If done well, the pre-plea report helps to put the client's best foot forward and it gives the defense lawyer an advantage at the settlement conferences with the DA and Judge.
Of course, consult with your own lawyer in your own case for advice.
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