The baby was found dead on Friday inside a room where the parents stay, said Brigadier Thulane Ngubane.
“The family alleges that the child could have died due to inhalation of teargas smoke that was fired by public order police who were dispersing the protesting and illegally gathered crowd in Majakaneng,” said Ngubane.
“The information has it that the child, who was allegedly left with the father, was found dead… inside the room where the parents stay.”
A used teargas canister was found near the outside of the room.
Ngubane said it had never been proven that teargas could be fatal.
“The investigation regarding this matter continues and a pathologist will be involved to conduct the post-mortem in order to determine the exact cause of death,” he said.