Fadi does not believe in God, and he is terrified.

In a Baghdad cafe, the medical student sits far from other customers, and glances over his shoulder to make sure nobody is watching and listening.

“I am afraid of being discovered — then I would be killed,” he says in a voice that rarely rises above a whisper. “This may also harm my family, although none of them know that I don’t believe.”

Fadi, 23, says that he could be targeted for believing that God and all of the world religions are human inventions. To avoid detection, he deletes all searches on his computer and cellphone.

Like all of the 20 atheists NBC News spoke to, Fadi asked to be identified by a pseudonym to avoid being targeted by militias or police.

Although Islam is the state religion and it is against the law to slander or insult any faith, atheism itself is not illegal in Iraq, according to legal expert Ali al-Timimi. Anecdotal evidence suggests a small but growing community of Iraqi agnostics and atheists in the Muslim-majority country. One Facebook page called Iraq’s Agnostics and Atheists has nearly 13,000 likes and 17,000 followers.

But power, violence and religion are a toxic mix.

Many of Iraq’s unbelievers have been forced underground as religious hard-liners battle for control of the young democracy, which is struggling to balance the demands of both Sunnis and Shiites, plus smaller ethnic and religious communities.