This is actually a very old story. Those books were written in the nineties, when noone gave a flying toss about copyright. Or anything, for that matter. The authors stole stories from all sorts of franchises: there were books based on Batman and Robin, Friday the 13th, One flew over the cuckoo's nest, Aliens, A Nightmare on Elm Street, Lord of the Rings and even works by Castaneda!
They were written by different authors who sometimes didn't even know what the Turtles were. The heroes' appearance and characters were inconsistent: in one book they were mentioned to have beards and hair, in an another one they were three meters tall and bald. The books differed in their mood as well, as you can guess, ranging from serial murderer detective stories to some sort of a crazy brain-scooping nightmare or an Evil Dead ripoff.
Of course, such thing is utterly impossible nowadays because president Putin and Medvedev you all keep defaming so eagerly toughened copyright laws in Russia, to such extremes that you cannot publicly sing a song you own without paying a fee to some arbitrary commission. So relax, people, nobody's going to infringe your favourite copyrights anymore;-)