South Korean police have arrested a pastor who allegedly convinced 400 followers to flee to Fiji because a “great famine” was imminent on the Korean Peninsula but then forced her flock to take part in ritual beatings that left one member with brain damage.

Shin Ok-ju and three senior members of the Grace Road Church were arrested after landing at Incheon Airport in South Korea on Saturday.

South Korea’s Christian Daily newspaper reported that Mrs Shin is being questioned in connection with allegations that she confiscated the passports of the 400 members of her congregation who moved to Fiji in 2014. She reportedly refused to let them leave the 83-acre compound where they lived communally under the close watch of handpicked “guardians”.

She is also being questioned about the alleged ritual that church members knew as “the threshing ground”, in which followers were forced to beat each other until they were bloodied. Those who declined to take part would become the “target of God’s punishment”, they were allegedly told.

According to The Korea Times, former member claimed that one boy was forced to hit his father more than 100 times as part of the ritual, while another follower sustained brain damage as a result of the beatings.