I was wondering if anyone could find out who this person is? I cannot find this information and would really like to know.
Pro Football Reference has the information you need.
From the home page, click "Teams", then "Cincinnati Bengals." At this point, you will be on the "Cincinnati Bengals Franchise Encyclopedia" page. On this page, under the "Career Leaders" dropdown, click "Defense." From there, you can view and sort by a number of different categories. Given you are looking for the all-time leading tackler, you may sort by tackles (Tkl).
[Who is the] Cincinnati Bengals All-Time leading tackler?
Tim Krumrie with 1008 tackles.