I've been hunting for free mystery books online for ages, and let me tell you, the internet is a treasure trove if you know where to look. Project Gutenberg is my go-to—it's packed with classic mysteries like Agatha Christie and Arthur Conan Doyle, all free because they're in the public domain. The site is super easy to navigate, and you can download books in multiple formats.
Another gem is Open Library, which lets you borrow modern mystery ebooks for free, just like a digital library. You’ll need to create an account, but it’s worth it. For more contemporary titles, check out sites like ManyBooks or Feedbooks—they often have free promotions or indie authors offering their work. Just be prepared to sift through some lesser-known titles.
Don’t overlook Reddit communities like r/FreeEBOOKS either. Users frequently post links to free mystery novels, and some even compile lists by genre. It’s a goldmine for hidden gems. Lastly, if you’re into audiobooks, Librivox has free recordings of public domain mysteries, perfect for listening on the go.