The South African authorities are investigating the death of a Nigerian man who collapsed while he was being arrested by police in Cape Town last week.

The initial results from a post-mortem showed that Ibeh Chika Simon, 42, “sustained multiple bruises and abrasions on his back and chest”, according to the independent body that oversees police conduct.

Nigerian diplomat Ninikanwa Okey-Uche said her country was “deeply appalled by reports of the egregious police tactics that led to his death” on Thursday.

In its statement, Western Cape police said Simon died while he “was being placed under arrest [as] he allegedly became unwell and collapsed”.

Simon’s death comes amid heightened tensions between South Africa and Nigeria over allegations that Nigerians have been the target of xenophobic violence.

Earlier this month, the South African authorities confirmed the death of another Nigerian in June under similar circumstances.

In her statement condemning Simon’s death, Okey-Uche, Nigeria’s consul general in Johannesburg, called for a “transparent” investigation and alleged that there was “an alarming pattern of unresolved extrajudicial killings/deaths and unacceptable misconduct against foreign nationals”.

“Suspects are entitled to due process in a court of law; no authority should be above it”.

She also said there were reports that another Nigerian, Egwabor Patrick Chuks, was shot during same the operation and was in hospital with serious injuries. The Western Cape police said there was “no record of the incident”.

Describing the circumstances of Simon’s death, Western Cape police spokesperson Col Andre Traut, said that officers were conducting a search at a home in the area when they found an unlicensed firearm and what appeared to be drugs.