NEW DELHI (AP) — A former Jehovah’s Witness has been detained on suspicion of setting off an explosive device that killed three people and wounded 50 others at a denomination gathering in southern India, authorities said Monday.

Hundreds of Witnesses were at a local prayer session Sunday at the Zamra International Convention Center in the town of Kalamassery in Kerala state when the explosion took place. An improvised explosive device placed inside a tiffin box was believed responsible, the state’s top police officer, Sheik Darvesh Saheb, said.

The suspect was identified by police as Dominic Martin, a former member of the Jehovah’s Witnesses who posted a video on Facebook claiming responsibility for the blast before surrendering to the police. Martin, a local, said in the video he decided to carry out the blast because he feels the Jehovah’s Witness theology is wrong.

“They teach that all people of the world would perish and only they will live. What should we do with people who long for the ruin of the entire people in the world. I could not find a solution. I took the decision realising that this idea is dangerous to the country,” Martin said in the video.

Police said they were still trying to verify Martin’s claims of responsibility for the blast.

Jehovah’s Witnesses identify as Christians but are guided by distinctive beliefs and practices. They are known for their door-to-door proselytism.

India, with a population of more than 1.4 billion people, has about 60,000 Jehovah’s Witnesses followers, according to its adherents.