Neal Adams' checklist lists this as being a reprint from Detective Comics #402 (story by Frank Robbins, art by Neal and Dick Giordano), but I had always thought the DC/Power Record stories were all original.
Not having a copy of 'Tec #402, I can't check, but from what I've been able to look up, the story in that issue is listed at fifteen pages, but the story here is twenty pages long. Anybody out there have an answer?
Love that back cover!
Now with added PDF!