5,611 KB, 3,787 KB, 3,462 KB are all consistent with a normal mp3 size yet they are all reknown virus sizes spammed on the network. Yes they read as mp3 type but that's because they trick LW into thinking they are such. There's a couple other newer file sizes too.

Do they show bitrate? Do they show id3 tag with album title, year of release? Most spam has limited id3 tag information, if any.

Do a test ... do an audio search ... for artist ... type in random letters such as owyulcnolsy9iu7ie & see if you get similar search results. I'm sure some results will show you already have that file. lol