Sensors help police curb gang violence in Cape Town

One unfortunate consequence for communities living with high levels of gun violence is that many residents become so desensitised to the sound of shooting that the incidents are under-reported to police.

In gangland areas of Cape Town, such delays in contacting the authorities have proved a major stumbling-block to tackling gun crime, according to the city's safety and security chief, Alderman Jean-Pierre Smith of the Democratic Alliance party.

This is because unless the police are given a chance to respond quickly to the shooting, the culprits either escalate the situation, or slip away undetected after dispensing a few rounds of ammunition.

"Intelligence gathered by the authorities in our worst gang-affected areas has revealed that on average only one in six shootings were being reported to police," Smith told The Irish Times.

“Without a rapid response from the police, single-shot incidents turn into shoot-outs between multiple gunmen, and these situations often lead to a higher casualty list among the perpetrators and bystanders,” he said.

A good example of this, said Smith, occurred when some schools in Manenberg township closed last year because of gun battles they said were raging around them.

“The police had only 25 incidents of gunfire reported to them from the area over a number of weeks, but the schools had been counting and recorded hundreds of shots over the same period,” according to Smith.

Indeed the death toll associated with gang violence in Cape Town is staggering. In 2014, 465 gang-related murders were recorded in the city, which accounted for 15.4 per cent of all homicides recorded there that year.

To try to reduce the number of deaths and restore order, the city has been piloting a US-developed gunshot detection technology called ShotSpotter in some of its worst gang-infested areas since the beginning of the year.

In January the sensor-based technology was deployed over seven-square kilometres in Hanover Park and Manenberg on the Cape Flats, two townships with high levels of gang activity, and by the end of September both areas had recorded a massive reduction in gun crime.

According to the city, the number of recorded gunfire incidents in Manenberg dropped from 133 in June, to 22 incidents in September, while in Hanover Park, recorded gunfire incidents fell from 86 to 33 over the same period.

Determining the origin of gunfire using sound is not a new phenomenon, having first being used in the First World War. But today’s approach has evolved dramatically, combining high-level technology involving multiple sound-monitoring microphones, which detect gunfire based on algorithms.

If ShotSpotter’s sensors pick up anything in the areas it is deployed, the audio recording is sent to a 24-hour monitoring center in Newark, California. Here it is reviewed by experts who then transmit the location of confirmed shots back to local police officers.

This takes about 30 seconds, says ShotSpotter on its website, which is far faster than the typical 3-5 minutes it usually takes the first person to call the police or emergency medical services once a shot is fired.

Smith explained the while ShotSpotter technology is not a “magic bullet” to tackle crime, it has added a new dimension to the police’s ability to monitor crime-ridden areas more effectively, and also to their efforts to prosecute those responsible for the shooting.

It seems that when combined with high-quality CCTV, drone technology, community policing initiatives, and rapid response policing units, ShotSpotter is giving local law enforcement a serious edge.

“Now that we can pinpoint the gunshots our CCTV can home in on the location and our officers can respond with in one or two minutes. Our firearm confiscation rate has increased five-fold; trust levels between police and residents have increased; and the number of shots fired has decreased dramatically,” he said.

The pilot programme’s roll out has not been without complication, however. Criminal elements in the monitored areas are reportedly using firecrackers to confuse the ShotSpotter system, and to assess police response times before actually using their firearms.

Reducing gun violence in the Western Cape capital can also be hampered by the authority’s need to rely on eyewitnesses to identify the shooters and give evidence against them in court, Smith maintained. This is because their evidence is often unreliable due to the trauma of being caught up in such violent incidents.

But the increased trust built up between the communities and police is leading to officers getting more on-the-ground information that supports the accumulation of the forensic data needed for prosecutions.

Smith said the use of ShotSpotter in Cape Town is the first time the system has been used in Africa, although it was successfully tested in South Africa’s Kruger National Park as a way to tackling rhino poaching.

Cape Town has access to funding to continue implementing the system for the next three years, and it is hoped that law enforcement across the country will begin to avail of the technology to help fight gun crime in their areas.

“I think the system will be extended but we will have to review it. We hope that in future years a local supplier will come forward with their own type of shot detection system to make it cheaper for us to implement,” Smith said.