This handout from the Royal Thai Police taken on Sunday shows police in position near an escalator in the Terminal 21 shopping mall, as they attempt to locate Thai soldier Jakrapanth Thomma who went on a shooting rampage, in the Thai northeastern city of Nakhon Ratchasima. Photo: AFP

In a fourth-floor toilet of the Terminal 21 mall, shoppers jammed cubicle doors against the entrance to keep out a Thai soldier on a shooting spree, tracing his movements through fragments of CCTV passed on by friends on the outside.

Barricaded in the women's toilet with a few dozen others, Chanathip Somsakul, a 33-year-old music teacher, and his wife pored through social media and made frantic calls to friends and family.

Their daughter Chopin sat watchfully on a ledge, a three-year-old bystander to a mass killing without precedent in Thailand.

Nakhon Ratchasima, a mid-size Thai city entwined like much of the northeastern Isaan region by tight family connections and social media networks, quickly began to rally to its own trapped inside.

"A friend who works at the mall was talking to a guy in the CCTV control room... he gave us updates on the location of the gunman," Chanathip told AFP on Sunday.

Those details, shared over messaging apps, may have saved the lives of Chanathip, his family and the 20-30 others inside.

But in the swirl of competing information, dread gripped those hidden inside cupboards, storerooms and toilets across the mega-mall.

For hours, a killer stalked the concourses, the glass-fronted windows of the multi-level mall spider-webbed by bullet holes.

The gunman - a soldier apparently angered by a dispute over the sale of a house - had already slain several people on his way into the shopping center, the largest in the city and packed on the first day of a long weekend.

Sergeant-Major Jakrapanth Thomma swaggered through the mall, a machine gun slung over his shoulder and wearing a helmet and combat gear, in full view of CCTV cameras.

By the end of his spree at least 30 people would be dead - himself included. 

Many more are wounded, several critically.

Fear snapped through Chanathip's hideout when someone banged on the toilet door.

Chanathip had just finished teaching a music lesson and - like hundreds of others - was eating in the mall with his family when gunfire erupted.

His family took refuge in the women's toilet. Some men pulled the toilet doors off and wedged them against the entrance.

At 9 pm on Saturday they received word from police that they could leave, which they did - in an orderly fashion at first, along with dozens of others.

But gunshots rang out as they reached a car park, sparking a wild sprint.

Inside, scores of others remained trapped, cowering in gym toilets, under restaurant tables and in store rooms - hoovering up information on the whereabouts of the gunman.

AFP