In truth, I don't know. The research I've done for you on the topic doesn't look promising as far as online searches go, but is more promising as far as in-person/written requests are concerned.
While a lawyer/court could probably subpoena information about a particular trooper from the Professional Standards Division, it doesn't appear as though this information is PUBLICLY available in a searchable online format. That said, publication of that information is made to the person filing the complaint:
Will the individual who signed the complaint be notified of the outcome of the investigation?
"A: The complainant will receive a letter from the superintendent summarizing the results of the investigation. "
It also seems that "investigative" reports are public record, and may be requested from the Custodian of Records office. (http://www.mshp.dps.mo.gov/MSHPWeb/PatrolDivisions/CRID/pubRecChk.html). In-person inquiries are handled in Jefferson City, 1510 East Elm Street, Jefferson City, MO 65102-0568, but you can also mail a request to them or fill out an online request form. There appears to be a charge for this service, but you have the right to inspect records for free before you purchase or copy them. I don't know how much purchase or copying costs, but the phone number for viewing appointments (573-526-6167) might be able to answer that question or direct you to someone who can.
Thanks for the question, it was good to have a chance to learn something about the process. Good luck!
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