Send your request to support@inmatessearcher.com. Give your name, the state the listing shows, and enough detail to identify the record. Ask for deletion rather than suppression, keep the sent copy, and write down the date.
There's a useful thing to quote back at them. This site's own privacy policy carries a CCPA metrics table claiming a one-day median for answering requests like yours, across 111,614 of them in 2025. That figure is theirs, published on their own page, and it sits badly beside a form that has told every visitor to try again later for months. Mentioning it costs nothing and makes the reply harder to shrug off.
If a month passes with no answer, reply on the same thread rather than opening a new one, and say plainly that the website's own removal route does not function.