An elderly couple was on Friday found murdered in their Morningside home in Sandton, northern Johannesburg.
The man and woman, both in their late 70s, were discovered by their son just after 3pm.
Police believe they were killed by robbers, as some of their belongings appeared to be stolen.
Family relative Wolfgang Wollauz said friends of the couple became suspicious when the pair failed to arrive for a schedule meeting.
He said their son, who went to their home, found their two lifeless bodies.
“When he got in, he found his parents tied up and suffocated (with plastic bags).”
Police spokesperson Captain Kym Cloete said murder probes were underway.
“Motive and cause of death is still under investigation”
No suspects had been identified by Saturday 4pm.
Anyone with information can send their anonymous tip-offs to Crimeline on 32211.