A Christian pastor now based in Turkey shared one of his most unforgettable experiences while ministering to his flock after he fled Iraq in a recent interview with CBN News.

Ghassan Thomas, former pastor of the Christian and Missionary Alliance (CMA) congregation in Baghdad, said he fled Baghdad when Islamists threatened him and his family with death. He then joined other refugees to Turkey where he quickly started a new church to reach out to other refugees.

The pastor said while he was establishing his church in Turkey, he had an encounter with an avowed assassin and spy for the Islamic State (ISIS) jihadist organisation.

CBS News also interviewed the ISIS militant who identified himself only as "Mohammed."

He said he was sent by his ISIS commander in Iraq to spy on Thomas' church.

Before he undertook the spying mission, Mohammed confided that he was part of an ISIS unit assigned to execute infidels and enemies of the terrorist group in Iraq. After his men gun down the members of a family inside their home, his task is to go back to the house and finish off anyone who is still alive.

"In that time, I think in this way: I should kill. I should do many bloody things just to be close with my Allah," Mohammed told CBS News.

He explained that this lust for blood is what motivates ISIS. "If you are not a Muslim, you need to be a Muslim or we should kill you and take your everything – financial, women and everything. This is in the Quran."

When the fighting between ISIS and Iraqi government forces intensified, Mohammed said his parents feared for his life and told him to go to Turkey. It so happened that his ISIS commander also ordered him to go to Turkey to spy on Thomas' church.

Mohammed said he was unprepared for what happened next when he stepped inside the church.

"I saw the people, how they welcomed me and they don't know me," he recalled. "And I hate those people and they show me love."

Members of Pastor Thomas' congregation prayed for Mohammed—and the ISIS hitman and spy said this changed his life.

"When they pray for me, I start to cry like a child. And I feel like something come out of my body – very heavy," he said. "When I finished the service, I went home, but there is a person walk[ing] with me, just talking, but I feel like I'm not on the earth. I said, 'am I flying? I don't feel like I'm walking. Like someone carry me.'"

Then Mohammed began reading the Bible and comparing it to the Quran.

"I went there and discovered this is the God I'm trying to find. This is the true God. This is what I want for my life," he said.