"I do not trust [President Jacob] Zuma. The police must investigate this, not some politically motivated commission. This is the way it is supposed to be done," Malema said.
"The person who established this commission is not an honest man. He established it to arrive at certain conclusions."
Malema was speaking before entering the Marikana police station with residents and miners to lay murder charges against the police following Thursday's shooting at Lonmin's mine. Reporters were not allowed inside.
Last week, the platinum mining company's rock-drill operators in Marikana embarked on a protest that saw 10 people, including two security guards and two police officers, killed.
The protests culminated in clashes with the police on Thursday, in which 34 miners were shot dead, more than 70 injured and 260 arrested.
Zuma set up a judicial commission last week to investigate the shooting.
Malema said some police officers were prepared to conduct the Marikana investigation, if given the opportunity.
"I spoke to some of the police. Some were there on the day and some were not. They said they were not happy with what happened and would investigate the matter if given a chance."
The protests were believed to be linked to rivalry between the National Union of Mineworkers and the Association of Mineworkers and Construction Union over recognition agreements at the mine. Workers also wanted higher pay. – SAPAPost published in: Africa News