Madurai: Five men have been booked after a 23-year-old man died by suicide hours after he was allegedly assaulted and threatened in the name of caste in Thirumangalam, police said.The case was registered by Thirumangalam police on Aug 17 following a complaint from Kamuthai, mother of the deceased Azhagupandi. Three accused — Karthick, Kamalakannan and Yogeshwaran — have been named, while two others remain unidentified.Police said Azhagupandi left home around 8pm on Aug 16, and returned about 50 minutes later, telling his mother that five men had assaulted him. The FIR does not state what triggered the initial confrontation.The complaint said the group later came to his house, where Kamalakannan allegedly assaulted Azhagupandi again. Yogeshwaran was accused of attacking one of his relatives. Using casteist slur, Karthick allegedly threatened to behead Azhagupandi. Kamuthai told police that her son remained frightened after the threat and repeatedly spoke about it.Around 11.45pm, she found him hanging inside the house, according to the complaint. Police booked the five under BNS provisions including abetment of suicide, assault, rioting and criminal intimidation, besides provisions of the SC/ST (Prevention of Atrocities) Act.