Another option could be Amazon Kindle Direct Publishing. It allows you to self - publish your crime fiction stories easily. You can reach a large number of readers all over the world. Plus, you have more control over the publishing process, from cover design to pricing.
One great place to publish short stories is 'Literary Magazines'. There are numerous literary magazines out there like 'The New Yorker', 'The Atlantic' etc. They have a wide readership and are respected in the literary world. They often feature works from both established and emerging writers, which gives new writers a chance to get noticed.
The online platform Clarkesworld Magazine also accepts science - fiction novel submissions in some cases. It has a dedicated readership of science - fiction fans. If your science - fiction novel is in the form of a serial or has a strong short - story - like structure, it could be a great place to start getting your work out there. Additionally, being associated with Clarkesworld can enhance your credibility in the science - fiction writing community.
Traditional publishing houses that specialize in science fiction or speculative fiction could be an option. But getting accepted can be quite competitive. Another choice could be self-publishing through platforms like Amazon Kindle Direct Publishing, which gives you more control but requires marketing efforts on your part.
You could try publishing on well-known platforms like Kindle Direct Publishing or Smashwords. They have a wide reach and can expose your work to a large audience.
I think it depends on your goals. If you want broader distribution and potential for big sales, going through a major publishing house might be ideal. But if you want to build an audience quickly and have more creative freedom, self-publishing on sites like Webnovel or Royal Road can be great.