Two men were killed by an angry mob in Noordgesig, Johannesburg, on Wednesday night.
According to JMPD spokesperson Senior Superintendent Wayne Minnaar, it is unclear why the men were attacked and killed by the mob.
Eyewitnesses on Twitter claimed the men were caught stealing tyres, but Minnaar could not confirm this.
"Why they were murdered and how they were murdered will have to be investigated," Minnaar told News24 on Thursday morning.
The mob then vented their anger at passing vehicles on on Main and New Canada Road, pelting them with rocks.
No injuries have been reported.
"New Canada Road is a main road in the area and it was affected last night. But protests died down at around midnight and the situation is calm.
"There are many officers monitoring the situation. Motorists can safely use the road [on Thursday] morning," Minnaar said.