Eight people found dead in Texas truck

Eight people were found dead yesterday inside a truck in a Walmart parking lot in San Antonio, Texas in what police said appeared to be "human trafficking crime."

Another 28 people were injured -- 20 of them severely -- and were being treated at seven local hospitals, San Antonio Police Chief William McManus  told reporters.

The police chief said the group included children, but later told CNN that the eight dead were adult men.

He said the truck driver had been arrested.

"We got a call from a Walmart employee about a welfare check in a tractor-trailer that was parked on the lot here," McManus told a news conference.

"He was approached by someone from that truck, who was asking for water."

The employee returned with the water and then called the police who "found eight people dead in the back of that trailer," the police chief said, calling it a "horrific tragedy."

It was not immediately clear how many people may have survived and fled, McManus said.

San Antonio lies a few hours drive from the border with Mexico's Nuevo Leon state. Weather in the area has been hot and dry.