I've come across this sentence in my manga.
そ そうか そういう疑いを持っているのか
It's actually fairly easy, but the particle at the end has confused me. I thought it was the two particles
か, but then I saw this in a dictionary:
のか - Particle - endorsing and questioning the preceding statement (sentence ending particle); lamenting reflections on the preceding statement (sentence ending particle)
That seems to fit, because it's at the end of the sentence, and he's commenting on what another character said to themselves. But beyond that, I have little idea of what this means. Is it actually a question particle similar to か? When would you use this instead?