A gunman described as a disgruntled Walmart employee fatally shot two co-workers and wounded a police officer before he was shot and arrested Tuesday at a Walmart store in northern Mississippi, authorities said. Southaven Police identified the suspect as Martez Abram. He has been charged with two counts of murder.

Southaven Police Chief Macon Moore said Abram shot a Southaven police officer, who was protected by a bulletproof vest and suffered minor injuries.

"He was saved by his vest," Moore told reporters during a press conference. The chief said a second Southaven officer shot the suspect twice, and that Martez was undergoing surgery at a hospital in neighboring Memphis, Tennessee.

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Both the people killed were Walmart employees, Moore said. Employees told The Associated Press that the first was shot in the parking lot and the second was shot inside the store.

Southaven Mayor Darren Musselwhite described Abram as a disgruntled worker with a grievance against his employer. CBS affiliate WREG-TV reports the man was suspended on Monday after pulling a knife on a customer.

Martez Abram Southaven Police Department

"It wasn't an accident," said Travis Jones, an overnight stocker who was working when he heard shots. "He knew what he was doing when he came in there."

Jones said he saw the body of store manager Anthony Brown on the floor as he ran out of the store. "It was an ugly scene," he said.

DeSoto County Coroner Joshua Pounders said the 40-year-old Brown, an Olive Branch resident, appears to have died from a gunshot wound. Nicholas Gales said the other slain worker was his brother, 38-year-old Brandon Gales of Hernando.

Brandon Gales' father told WREG-TV his son was a father of three. Jones called Brandon Gales his best friend and an "all-around good guy."

The shooting at about 6:30 a.m. brought a massive police response to the shopping complex at a busy exit off Interstate 55 in Southaven, a suburb of 55,000 people. Carlos Odom, 35, had just made his usual visit to his cousin, who works there, and said he was leaving when he heard more than a dozen shots.

"I just hear gunshots," Odom said. "Pow. Pow. Pow. Pow. Pow."

"When the cops run into the Walmart, you hear more gunshots," Odom said. "After that, it stopped."

Brandon Gales, left, and Anthony Brown are seen in a combination of photos obtained by CBS affiliate WREG-TV.

Odom said he ran out into the parking lot and later spoke by phone with his cousin, who told him one of the victims was an employee and the gunman worked there as well. Phil Cox, 70, said he had just bought some nasal spray and was in the parking lot when he thought he heard a gunshot and then saw a man who may have been the shooter run into the store.

He got into his truck to leave as police began arriving. "Everything went crazy at that point," Cox said, expressing sympathy for employees. "It's just hard to believe what happened here, but it seems like it's happening everywhere."

Officers kept working to clear the store hours after the shooting, Moore said, in part because they found a suspicious package and called in a bomb squad. Moore said about 60 employees were working at the time.

They were taken to the parking lot of an adjoining Chili's restaurant and interviewed by officers, remaining there for hours. Some embraced, while one was placed in an ambulance.

People gather outside a Walmart in Southaven, Mississippi after a shooting on July 30, 2019. Jerrita Patterson/WREG

Others gathered in a circle to pray. Finally, authorities brought employees back into the store after noon, spoke to them and released them to go home.

The store remained closed, even as businesses operated as usual elsewhere on the high-traffic suburban strip. "The entire Walmart family is heartbroken by the loss of two valued members of our team," Walmart U.S. President and CEO Greg Foran said in a statement Tuesday afternoon. "We feel tragedies like this personally, and our hearts go out to the families of our two associates and the officer who was injured."

The company was relieved the suspect was apprehended and appreciates the quick response by authorities and its employees, Foran said. "We'll continue to focus on assisting law enforcement in their investigation and on supporting our associates," he added.