The killer of the South African anti-apartheid leader Chris Hani has been stabbed in prison, days after the country’s top court ordered him to be released on parole, the prison service said. In a statement, the Department of Correctional Services said on Tuesday it was “able to confirm an unfortunate stabbing incident” involving Janusz Waluś, who has spent nearly three decades in jail for the 1993 killing. Waluś, 69, had been due to be released by Thursday under last week’s order by the constitutional court. The prison service said he was stable and receiving necessary healthcare. “It is alleged that Waluś was stabbed by another inmate from the same housing unit,” it said, adding that investigations were under way. Waluś was handed a life sentence for the murder of Hani, a hugely popular figure and fierce opponent of the apartheid regime. Hani was shot dead in the driveway of his house a year before South Africa’s first multiracial elections. The shooting occurred just as negotiations to end apartheid were entering their final phase, stoking tensions that some feared would erupt into civil war. Last week, South Africa’s top court controversially ordered Waluś, who had immigrated from then communist Poland, to be released on parole. The decision was described as “diabolical” by Hani’s widow and sparked bitter protests by the ruling African National Congress (ANC) and South African Communist party (SACP), which were in the forefront of the fight against apartheid. At the weekend, Hani’s gravesite and memorial in a suburb east of Johannesburg were vandalised. In a joint statement with trade unions, the ANC and SACP condemned the attack and said it came in the context of a judgment that “pleased unrepentant apartheid perpetrators”. On Monday, the home affairs ministry announced Waluś would have to serve his parole in South Africa, saying he should not be allowed to return home to Poland given the “heinous crime committed”.