South African police said on Tuesday the death of a Nigerian man in custody late last month had nothing to do with a surge in anti-migrant violence and that he collapsed after being arrested for drug possession.Nigeria’s foreign ministry alleged on Sunday the man had died during an interrogation by South African police two days before nationwide rallies against undocumented migrants, threatening unspecified action if there were more attacks on its citizens.“The South African Police Service strongly rejects attempts to link this incident to anti-illegal immigrant protests,” a police spokesperson said in a statement.The spokesperson said a police drugs team had arrested the Nigerian at his apartment in an intelligence-driven operation. Drugs were found at the scene, and the man collapsed while being taken into custody in a Pretoria police station, the spokesperson added.Paramedics were called and declared him dead, and a police watchdog was notified and will investigate the incident, the spokesperson said.South Africa’s foreign ministry has said Nigeria’s government should send in any evidence it has about the man’s death but has not commented on the specific allegations made by its Nigerian counterpart.The anti-migrant protests over the past few months have been mostly peaceful but at times turned violent, with attacks on foreign nationals and looting of foreign-owned shops.Rights groups say foreigners are being used as scapegoats for deep-rooted problems like crime and unemployment.