Three people have been taken in for questioning in connection with the kidnapping and murder of two toddlers in Diepsloot, north of Johannesburg, Gauteng police said on Wednesday.
Police are also searching for a fourth person, Lieutenant Colonel Lungelo Dlamini said.
Police were also investigating a possible link between the murders of young girls in the area.
In September, a five-year-old girl was found dead in the same area.
"It is suspected that she was sexually violated and strangled. A suspect who was taken in for questioning relating to the murder was later released," Dlamini said.
He said although police suspected that the two girls were strangled, they would wait for the post-mortem results to confirm how they died.
Investigating the murders
He said the area was calm following protests by residents on Tuesday.
"There has been no incidents so far since last [Tuesday] night."
Angry residents took to the streets and blocked roads in the township.
The two girls, aged two and three, were reported missing at the weekend.
Their bodies were discovered by a resident in a toilet cubicle on Tuesday at around 5am.
A team of detectives has been appointed to investigate the murders, said Dlamini. – Sapa