By Peter Szekely

(Reuters) – The gunman behind Thursday’s mass shooting near Memphis, Tennessee, was a third-party vendor for the Kroger (NYSE:) supermarket where he shot 15 people, and one fatally, and had no history of violence, authorities said on Friday.

They said that the shooting on Thursday in suburban Collierville shocked everyone. Employees and shoppers ran for safety, hiding behind freezers or aisles, before the gunman took his life.

The initial victim count was increased by two to fifteen, including Olivia King who, as a widow, had three sons. Other victims were treated at local hospitals and fought for their own lives.

Collierville police chief Dale Long said that his prayers had been answered. “We didn’t lose anyone overnight. There’s still some people battling.”

The Commercial Appeal newspaper reported that three victims were in critical condition on Friday.

Lane indicated that the police were still looking for evidence in the area, including at the house and vehicle of the suspect. He declined to give his name. Uk Thang was however identified as the shooter by a town spokeswoman.

The gunman had a history of some misdemeanor arrests, “but nothing for violence or anything like that,” Lane said.

Witnesses claim Thang shot at the people in the store with a rapid-firing gun. The gunshot wound he sustained was believed to be self-inflicted, according to the authorities.

Asked what could have prompted the shooting spree, Lane said, “We’re getting a clearer picture of what’s occurred, but I’m not ready to release that yet.”

The violence was the latest in a string of deadly workplace mass shootings that have erupted in U.S. cities, claiming dozens of lives this year and leaving many wounded.

Ten people were killed in March when a gunman opened fire at a King Soopers supermarket owned by Kroger Co in Boulder, Colorado.

Lane believes that the mass-shooter exercise conducted for first responders in the area on June 4 could have saved lives. It may also have made it easier to get medical attention faster to those who were injured.

“There’s no doubt in my mind that that training served us well yesterday,” he said.