One note, however: Official documents are not always in third person, occassionally using 'we' to refer to official departmental positions, or 'I' in the case of an investigator's personal opinion into the events that transpired (a internal police report often acting as a memo from the investigator to anyone in the future that will do a further investigation.)
I bring up this point because I am likely to do a inquiry into a well-publicized bank shooting, the report for which would not genuinely third person. Much of the description would be, but findings and conclusions would not be.