Zikalala said Magaqa's death was an embarrassment to the ANC.
The Times has learned that high-profile politicians close to Magaqa, including KwaZulu-Natal MEC for community safety Mxolisi Kaunda, had approached the Hawks with allegations that Magaqa had been poisoned after being shot.
"Individuals who are politically closer to him, including the safety and security MEC, suspect that he might have been poisoned [but] there is no evidence.
A pathologist has been appointed to refute or confirm the suspicion," a source said.
KwaZulu-Natal department of community safety spokesman Kwanele Ncalane said that Kaunda had spoken to the police but denied that he suspected poisoning.
National Hawks spokesman Brigadier Hangwani Mulaudzi confirmed that the possibility of poisoning was being investigated.
"We have heard [that he was poisoned]. We have to do a postmortem. We will know for sure after that."
- Additional reporting by Matthew Savides
The killing fields of KZN
At least 10 high-profile KwaZulu-Natal politicians have been murdered since January.
March 6: Sibusiso Sithole, Richmond municipal manager;
April 4: Thandazile Phoswa, Richmond deputy mayor;
April 23: Khaya Thobela, Umzimkhulu municipality speaker and ANC deputy secretary in the Harry Gwala region;
May 11: Khaya Gcwaba, former Umzimkhulu councillor;
May 23: Mduduzi Shibase, Umzimkhulu councillor;
June 8: Florence Nene, Umzimkhulu councillor killed in a mysterious car crash;
June 29: Sifiso Mkhize, Richmond councillor, attacked; died the next day;
July 13: Sindiso Magaqa, a former ANC Youth League secretary-general and Umzimkhulu councillor, shot with two other councillors: Nonsikelelo Mafa and Jabu Mzizi. He died in a Durban hospital on September 4;
August 8: Ntokozo "Lithi" Maphumulo, former Umdoni councillor;
August 30: Kwazi Everlast Mkhize, Umkhambathini councillor.