A court heard how a man whipped himself until he bled during a Muslim religious ceremony before allegedly forcing two boys to do the same.
Syed Mustafa Zaidi, 44, is accused of encouraging the boys, aged 15 and 13, who cannot be named for legal reasons, to beat themselves at a community centre in Levenshulme, Manchester, on January 19.
A 20-minute film of the event, entitled 10th Muharram Jaloos Longsight, was played to the jury of five men and seven women at Manchester Crown Court.
Zaidi flogs himself with a zanjeer zani, an implement which has a wooden handle with chains and blades attached, until his back becomes bloody from the cuts.
Participants at the men-only event take it in turns, in small groups, to flog themselves, while the crowd around them chant the name of Husayn, a central figure in the Shia faith whose death they are commemorating.
Some men are openly crying during the chanting. One man with a bloodied back kneels against a wall and sobs, another has plasters on his back. Another man has his back squirted with antiseptic spray.
The film also shows the 13-year-old boy flogging himself with the zanjeer zani.
Andrew Nuttall, prosecutor, said the 15-year-old boy, who is not seen in the film but was allegedly forced to take part in the ceremony, suffered multiple lacerations to his back and shoulders, including a wound measuring up to 1cm.
Mr Nuttall said Zaidi then went on to encourage the 15-year-old boy to flog himself and gave him 'no choice' about participating in the ceremony.
He said Zaidi took the arm of the 13-year-old boy, took off his T-shirt so he was bare chested and put the zanjeer zani in his hand and told him to flog himself.