Three men appeared briefly in the Klerksdorp Magistrate's Court on Monday in connection with the murder of ANC North West official Obuti Chika, the Hawks said.
They would be back in court on Tuesday for a formal bail application, said Hawks' spokesman Paul Ramaloko. They remained in custody.
The would be joined at their next appearance by a person arrested on February 14.
The three men were arrested on Saturday on charges of conspiracy to commit murder.
“We hope that these arrests will lead to the arrest of the main suspect in Chika's killing,” said Ramaloko.
He said that as the arrests made so far were the result of the Hawks' efforts, a R200,000 reward was still on offer to anyone able to help the police arrest the murderer.
Ramaloko would not provide the names of the people arrested, and said these would be released when they appeared on Tuesday.
However, the ANC Youth League said on Sunday that its North West chairman Papiki Baboile was among those arrested.
“Comrade Baboile is charged with alleged conspiracy to commit murder,” spokeswoman Khusela Sangoni-Khawe said in a statement.
Sangoni-Khawe said that the ANCYL “believes in the rule of law and has confidence in the criminal justice system”, and she called on its members to work with the police.
She said Baboile remained innocent until proven guilty.
The ANCYL trusted that the matter would be “speedily brought to conclusion”.
Chika, 33, was shot at point-blank range in the driveway of his home in Alabama, Klerksdorp, on December 14. He died at the Klerksdorp Hospital shortly after his arrival.
He was the ANC's regional secretary in the Dr Kenneth Kaunda District Municipality. - Sapa