First post on this forum, only just found it, but since I was always a huge fan of DM and its sequels it is good to see so many fellow fans

Appologies if this question has been asked before, I'm sure it has, but I couldn't find it posted on this forum anywhere...
My question is this, I know DM, CSB (etc) are downloadable from a site who's URL is posted often on this forum. However, the site makes no mention of copyright issues, and I'm sure someone somewhere owns the rights, so surely this isn't legal? Unless perhaps you own original copies?
I used to own original copies back when they came out. But my old amiga died beyond repair many years ago and I threw it out (I know, stupid) and have since got rid of all my old games... The only thing I can think to do is hunt down second hand copies, which if I then own I presume means its okay to download the emulator copies...
Any advice gratefully received,
Cheers
Oid