We see atheist and Christian heroes in Dostoyevsky's books. In many cases the works of an author reflect elements of their own life. However, the extent to which this occurs vary by author. Especially, in this instance where he has portrayed both atheist and Christian heroes, his own religion does come to mind. So, was Fyodor Dostoyevsky an atheist or Christian?
Note that questions asking about authors' life with relation to their works are on-topic
Fyodor Mikhailovich Dostoyevsky, author of such works as Crime and Punishment and The Brothers Karamazov, was a devout Orthodox Catholic from a very young age. He is reported to have, at a young age, recited prayers to guests to their great amazement. He is also said to have been greatly affected by various Bible selections. Through his time in the military academy, he continued the devout lifestyle that he had developed as a child, reading religious texts on a regular basis. However, over time he developed beliefs closer to those of the old believers than the mainstream Russian Orthodox Church. However he later wrote various contradictory things such as:
[I was a] child of unbelief and doubt up to this moment, and I am certain that I shall remain so to the grave.
and
[E]ven if someone were to prove to me that the truth lay outside Christ, I should choose to remain with Christ rather than with the truth.
However, later during his Siberian exile he again publicly revered Christ. However, he avoided churches and institutionalized religion. At no time though, did he become stuck in his ways. At times, he explored other religions, including Islam through reading the Quran. He described himself only as a "philosophical deist". However, his writings in The Brothers Karamazov where he states belief in the holy trinity brings into question his understanding of the terminology he used.
Unfortunately much of this is sourced from a few Wikipedia articles because the sources they used are not available to me in this location because they are all print books, which are not to be found in libraries near me.
Fyodor Mikhailovich Dostoevsky was never a Catholic. He was always an Orthodox Christian. In fact, Dostoevsky criticized Catholicism in many of his works for the reasons scholars of history of the Christianity can understand easily.
The older and wiser Dostoevsky got, the more he understood God the same way Orthodox Believers of Old Rite do. Old Believers are not some kind of sect, they actually are the original Orthodox Christians who rejected the church reforms in 17th century, when the Russian Orthodox Church decided to “modernize” and become a convenient tool of the state. Old Believers understood that such reforms would only keep people from real faith by having them engaging in more transactional behavior with the church, thus undermining the whole idea of faith and life in Christ.
Dostoevsky understood this when he observed the officially Orthodox Christian Russia of the 19th century being easily consumed by the shallow and evil ideology of Marxism. He understood that official church in Russia then failed its people completely.
This is why Dostoevsky wrote 12 great novels (think of the 12 apostles), sending them off into the world that was being destroyed by Marxism and atheism in front of his own eyes. This is why he created so many characters that were representing so many interpretations of Marxism by different folks - Dostoevsky was meeting his readers at their level first, so that he could then carefully guide them to Christ. This is why he created Zosima, Tikhon - those were the few characters he actually spoke directly through in his Karamazov Brothers and Demons.
Most of the other characters and heroes in his works were all either lost or looking for their answers, some - like Prince Myshkin or Alyosha Karamazov, or Darya Shatova, were closer to God than others, while Stavrogin, Pyotr Verkhovensky, Raskolnikov were too far from God.
