My suggestion is that either reporter gets access to the report he/she has made under reported items and gets ability to participate in commenting at that specific report.
When a staff member click the "Claim and handle report" button and makes the final comment. That comment should gets forwarded to the reporter. Either in a shape of an alert or a personal message.
That behavior can courage to make further reports if necessary and they would know that Staff members are actually value all the reports been made.