According to a Russian daily, Mikhail Kalashnikov wrote a letter more than six months before his death expressing repentance for his design of the AK-47 assault rifle.

“My spiritual pain is unbearable,” Kalashnikov wrote in a letter to the head of the Russian Orthodox Church, Kirill I, according to the Jan. 13 issue of Izvestia.

“I keep having the same unsolved question: since my rifle killed people, can it be that I... a Christian and an Orthodox believer, was to blame for their deaths?”

Kalashnikov was was born in 1919 in Soviet Russia, and fought in World War II, eventually becoming a weapons designer.

His AK-47 is among the most widely used firearms in the world, and has long been popular in less developed countries for its simplicity and reliability; it was used by North Vietnamese forces in the Vietnam War. He had long abjured responsibility for the gun's uses.

Kalashnikov died Dec. 23, following a hospital admittance for internal bleeding. He was 94.

Izvestia provided an image of the letter written to Patriarch Kirill, which the BBC said is typed on Kalashnikov's personal writing paper and is signed by “a slave of God, the designer Mikhail Kalashnikov.”

Nearing his death, it seems Kalashnikov was troubled by the problem of evil, reportedly writing, “The longer I live, the more this question drills into my brain, the deeper I go in my thoughts and guesses about why the Lord allowed man to have the devilish desires of envy, greed and aggression.”

He noted that despite the “increasing number of churches and monasteries”  in Russia, “evil still does not decrease.”

He went on to praise the Russian Orthodox Church, which he said brings “kindness and mercy” to the world. Kalashnikov lauded Kirill, the Patriarch of Moscow, for his “pastoral wisdom” and assistance to the Russian Orthodox laity.

Raised in the Soviet Union, Kalashnikov was not baptized into the Russian Orthodox Church until he was 91.

“The Lord showed me the way in the afternoon of my life … when at the age of 91, I crossed the threshold of a church, my soul felt as if it had been there before.”

His letter recounted planting a sapling from his birthplace, the Siberian village of Kurya, at a church in his home, Izhevsk, located 750 miles east of Moscow.

“People will look at the church and the tree, and think about the proximity of these two eternal symbols of goodness and life. And my soul shall be joyful, watching from the heavenly heights for this beauty and grace.”

Izvestia was told by Patriarch Kirill's spokesman, Alexander Volkov, that the patriarch had replied to Kalashnikov, calling him a patriot and telling him that the Russian Orthodox have “a very definite position: when weapons serve to protect the Fatherland, the Church supports both its creators and the soldiers who use it.”