Simonson, Morgan and Rodier introduce some new, super-powered members for the Special Crimes Unit in Adventures of Superman 569 (July 1999).
Riot makes a brief appearance right at the start of this issue.
The new members are not very impressive, even though the rest of the issue is devoted to introducing them. Both Maggie Sawyer and Dan Turpin are not happy about the idea of super-powered policemen.
To be honest, I have no recollection of them ever appearing again. But I have not read all the issues from this period yet. I didn’t care for it when it was coming out, and this issue I only read today for the first time. So I suspect we will see Freight Train, Fireworks, Badmouth and the Roo again.