Atomix Productions (now Atomix VirtualDJ) still holds the copyright. Distributing a "free download" of version 5.0.7 without a license is technically software piracy. While the company rarely sues individuals for using this ancient version, downloading it from torrent sites puts you at legal risk via your ISP.
Virtual DJ 5.0.7 is a legacy build of the popular DJ software developed by Atomix Productions. Specifically, version 5.0.7 (often part of the 5.2 update chain) was the last of the "classic" interface designs before the company moved to a heavy database-driven model (version 6). Virtual Dj 5.0 7 Free Download