Johannesburg police have identified the gang that killed a Seychellois airline manager at the Rivonia offramp from the N1 highway on Saturday night.
"Behind the scenes, a lot is going on to try and apprehend the suspects," said Superintendent Chris Wilken.
But identifying them, establishing where they were from and apprehending them took time.
"There is a lot of investigation taking place - looking at ballistics and the modus operandi."
There was a "strong possibility" they were the same gunmen who shot dead Cape Town motoring journalist Megan Herselman at the same place last month.
"You don't have to be an expert to link the two cases."
It was unlikely they would strike there for the next two or three weeks, but would probably move to another area.
"At the moment we don't want to create chaos by saying each and every off-ramp is a hotspot," Wilken said.
However, the junction at Alexandra was another one.
Wilken said undercover police were stationed at the Rivonia off-ramp, but were unable to be there 24 hours a day.
"... Nowhere in the world does it work," he said.
The highway patrol was also keeping an eye on the off-ramp, he said after an in-depth police meeting on Monday morning about the goings-on there.
Developments looked "very positive". Wilken would not go into more detail for fear of jeopardising the investigation.
He said both cases were being investigated by the serious and violent crimes unit, which was working round the clock to make arrests.
In both incidents, the vehicles had been stationary and their drivers on their cellphones asking for directions. The phones and their wallets were taken.
That their attention was not on the road, but on the people they were speaking to had made them "sitting ducks", he said.
He advised motorists not to stop at the side of the road if they were in difficulty, but to carry on driving to a well-lit place, a police station, or petrol station which at least had "some protection" and where they would be "relatively safe".
Among the precautionary measures being considered at the Rivonia off-ramp was improving the lighting. "It is very dark there," said Wilken.
That was not a police problem, but something the council would have to see to.
He said pamphlets were distributed on international, but not domestic, flights to Johannesburg warning people against going to areas with which they were not familiar.
There were no plans at the moment to erect crime hotspot warning signs at the Rivonia off-ramp.
It was "easy" to put up a sign, but the police were trying to look at the bigger picture as part of the build-up to the 2010 Soccer World Cup.
If there was a warning sign at every other off-ramp, people would leave their cars at home and there would be no vehicles on the roads.
"We must be realistic as well," said Wilken.
Meanwhile, the Herselman murder has spurred a South African magazine to launch a Unite Against Crime Petition to President Thabo Mbeki and Safety and Security Minister Charles Nqakula.
"We, the citizens of this country have had enough. We will no longer tolerate the unacceptable crime rate with which we live," the You/Huisgenoot-initiated petition reads.
"We are South Africans and we will not leave," it continues in an apparent reference to Nqakula's remark in March that people who "whinged" about crime should leave the country.
He later explained that the words were directed at three "negative" opposition MPs taking part in the debate during his budget vote.
"Our children have the right to play safely in their neighbourhoods," the petitioners implore.
"We have the right to drive our cars without being hijacked. We have the right to chat to a neighbour over the fence, without a stray bullet killing us."
This, while Quintin Hall, 12, recovers in a Benoni hospital after being shot in the stomach as he tried to help a woman hijacked while he and his mother looked at a townhouse for sale.
"We have the right to be safe in our homes, without electric fences, burglar bars and alarm systems making us feel like prisoners," the petition adds.
"We have the right not to be murdered. We have the right not to be raped. We have the right to safety and security and we are being denied this fundamental human right.
"We, the citizens of South Africa demand to be heard." - Sapa