"It just sounds like from our investigation, it is truly a tragedy," Captain Terry Parker of the Lumberton Police Department said Tuesday.

But the events that unfolded there just before 11am Sunday touched a nerve far beyond region, reflecting a growing concern around the country about gun violence, particularly involving children. Many of the shootings happen when young people pick up and play with guns they find in stores, cars or residences.

The shooting took place at the Brother's Minit Store in Lumberton, a small city of more than 21,000 people about 150 kilometres south of Raleigh, North Carolina. Brother's Minit is the kind of store where customers are known by name and can stop in for everything from phone covers to tobacco and snacks.

The Trace, a website that compiles national statistics in its Gun Violence Archive, said there were 692 incidents of children aged 11 years or younger killed or injured by gunfire in 2015, up from 628 in the 2014.

So far in 2016, such shootings exceed the number of days. The archive shows that as of January 11, there have been 19 shootings involving children aged 11 or younger. Among them was one in which an 11-year old boy was killed Monday night in a drive-by shooting at a housing complex in Alton, Illinois.

Most of the shootings were accidents, like when an adult drops a gun and it discharges, or when a child happens upon a gun. A two-year-old in Houston shot himself in the hand on January 3 when he picked up a gun his father was cleaning, and a nine-year-old in Trinidad, Colorado, was taken off life support on Sunday after he was shot in the head with a gun he and his brother found while sitting in a parked car.

Many states have rules intended to cover safe storage in addition to laws governing purchase and ownership of guns. North Carolina law requires owners to store firearms so children do not have access.

Parker said his department was trying to trace the origins of the handgun to decide whether to turn the case over to the Robeson County district attorney to determine whether charges are warranted. He said his officers were still gathering information, including about how the weapon had been stored and why it was in the store, He said his department had been called to the store one or two times in the past for shoplifting cases.