There is no question that the mass shootings in US schools and churches gain the most attention in America and around the world.

But they represent only a small percentage of the victims of gun crime.

Far greater in number are those killed in the relentless churn of gun violence in some of America's big cities.

Here, in contrast to the saturation coverage given to school shootings, the almost nightly carnage goes barely reported, so routine has the cycle of killing become.

In cities like Chicago and Baltimore the violence is barely newsworthy anymore.


And yet it is the grim reality of gun crime in America.

Now they have been joined by St Louis in Missouri, the new murder capital of this country, if figures compiled by a recent Police Chiefs Association survey are correct.

This is the murder capital of America

The city recorded 188 murders in 2016, or 60 per 100,000 people - 20 times the national average. Almost 70% of those murders occurred in certain suburbs of North St Louis where the population is 94% black and which suffers from the legacy of segregation and neglect.

It is one reason why we went to St Louis to report on what is happening in those areas. Another reason was the role of gun legislation - or the lack of it - in the increased murder rate.

It is very hard to ascribe changes in murder rates to any one particular factor.

But in Missouri researchers have found strong evidence that the repeal of one particular piece of legislation has had a profound effect on gun crime in St Louis.

It was a law that required tough background checks, including a review at the Sheriff's office, on all gun sales, including private deals.

Image: The city's murder rate in 2016 was 20 times the national average

In 2007 it was repealed and Daniel Webster, the director of Johns Hopkins Centre for Gun Policy and Research, studied the consequences.

He found that the lack of background checks on private sales resulted in more guns finding their way into the hands of criminals, and a sharp 25% rise in gun murders.

It included careful analysis of the kind of guns used by criminals in Missouri from 2007 to 2011. Mr Webster found an extraordinary rise in the number of relatively new guns being used by criminals, suggesting a link to the repealed law.

Sky's Mark Austin's full report from St Louis

The research also tapped into the profound differences between rural and urban Americans about guns. The repeal of the law was decided by a state legislature that is predominantly white and rural. Yet - if the research is to be believed - the impact of it was felt largely in the black northern suburbs of St Louis.

The families of victims in North St Louis have no doubt that the lack of background checks is the main reason for the explosion in the murder rate. Many told us the laws had become so lax that anybody could now get a gun very easily, sometimes without even producing an ID.

Image: North St Louis is a scene of abandonment and devastation

It is difficult to draw firm conclusions about research conducted in just one state.

It is true that in some states with relaxed gun laws, the murder rate is not noticeably high. But the experience of Missouri and what is unfolding on the streets of North St Louis, is too serious to be ignored.

And given expanded background checks are one of the demands of the students marching this weekend, it is particularly relevant. In North St Louis, poverty, neglect, drugs and unemployment all play into the crime narrative.

But guns, and the ease with which they can be obtained, are clearly a very significant part of the problem.