By ADRIAN SAINZ Associated Press

SOUTHAVEN, Miss. (AP) — 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 Chief Macon Moore said the man, whom he did not name, shot a Southaven police officer, who was protected by a bulletproof vest and suffered minor injuries. The chief said a second Southaven officer shot the suspect, who was then taken for surgery to a hospital in neighboring Memphis, Tennessee.

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 the suspect as a disgruntled worker with a grievance against his employer.

"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 a store manager on the floor as they ran out of the store. "It was an ugly scene," he said.

Nicholas Gales said the other slain worker was his brother, Brandon Gales. Jones called Brandon Gales his best friend, and described him as a father of four.

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."

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 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 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. Some embraced, while one was placed in an ambulance. Others gathered in a circle to pray.

"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 is 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.

Associated Press writers Jeff Amy and Jeff Martin in Atlanta contributed.