The deadly encounter in Hattiesburg, Mississippi, started normally enough, when a police officer pulled over a gold Cadillac Escalade with three people inside. But within moments, two officers lay bleeding in the street, two families were devastated, and police across the country were reminded of the risks they run every day.

The deaths of Hattiesburg police officers Benjamin Deen, 34, and Liquori Tate, 25, exemplify an element of patrol work that presages the mistrust between police and those they serve: the ever-present possibility of random violence, and even death.

Of the 50 officers killed by gunfire in 2014, eight were slain during traffic stops and 15 in ambushes, according to the National Law Enforcement Officers Memorial Fund, which tracks police fatalities.

“No traffic stop is routine,” Hattiesburg Mayor Johnny Dupree said Sunday afternoon.

Deen pulled over the Escalade about 8 p.m. Saturday, with brothers Marvin and Curtis Banks inside and Marvin Banks’ girlfriend, Joanie Calloway, at the wheel, police say.

Something prompted Deen to call for backup. Tate, a rookie, responded.

One suspect opened fire, according to Warren Strain, spokesman for the Mississippi Department of Public Safety. Then, police say, Marvin Banks stole a patrol car, driving the vehicle for a few blocks before abandoning it.

Hattiesburg residents Tamika Mills and Pearnell Roberts discovered the two fatally wounded officers and called 911, the Jackson, Mississippi, Clarion-Ledger reported.

“Never in my life have I experienced or seen anything like this except on TV, and to be in the midst of it, it’s shocking and heartbreaking,” Mills said. “As we were coming down Fourth Street, we noticed a bunch of lights. As we came on through, (Roberts) told me to turn around because she saw somebody laying on the ground.

“So I backed up. That’s when we noticed the officer was down. We just saw that one, but in the course of me being on the phone with 911, I turned and I saw another officer across the street rolling on the ground. (Roberts) ran across the street to check on him. He wasn’t all the way alert but he asked her, ‘Am I dying? I know I’m dying. Just hand me my walkie-talkie.’ ”

Deen and Tate died soon after arriving at a Hattiesburg hospital.

Police arrested the Banks brothers and Calloway at three different sites Sunday morning. Marvin Banks, 29, and Calloway, 22, each were charged with two counts of capital murder. Marvin Banks also was charged with one count of being a felon in possession of a firearm, and with grand theft on the allegations that he fled in the police cruiser.

Curtis Banks, 26, was charged with two counts of being an accessory after the fact of capital murder.

As police led Curtis Banks into a police station Sunday morning, reporters asked him questions. “No sir, I didn’t do it,” he said in response to one, the Clarion-Ledger reported.

A fourth suspect, Cornelius Clark, 28, was arrested hours later and charged with obstruction of justice, according to the Mississippi Highway Patrol.

All four are expected to appear in court Monday.

The slayings shocked Hattiesburg, a university town with about 150,000 residents in its metropolitan area. No Hattiesburg police officer had been killed in the line of duty for three decades.

The officers’ families were racked with grief.

Tate had graduated from the police academy less than a year ago, according to his father, Ronald Tate, of Atlanta.

“Man, oh God, I can’t begin to explain to you what that does to a parent,” Tate said in an interview. “You know, that just killed me, that took my time – the clocks, the hands – everything stopped moving. Sleep don’t matter no more, food don’t matter no more. I haven’t eaten, I haven’t slept, my body don’t care.”

Ronald Tate, an Army veteran and a security consultant, said he was in denial, afraid to leave Atlanta to come to Hattiesburg to face the inevitable grief. “I’m so scared I’m going to find my son was killed over nothing much,” he said.

Deen had been named Hattiesburg Officer of the Year in 2012 after rescuing a man from a burning home, his family said.

Known as B.J., Deen married his high school sweetheart, Robin, a family spokesman said. They had two children: a 12-year-old daughter, Melah, and a 9-year-old son, Walker.

It was the second time in five months that two U.S. police officers had been shot dead in the line of duty at once. On Dec. 20, two New York City officers were slain by a lone gunman as they sat in their patrol car in Brooklyn. The gunman, who had posted anti-police rants online, then committed suicide.

Strain said it was too soon to know why the Hattiesburg officers were killed. “We are less than 24 hours into this,” he said. “We are still considering every possibility.”

Gov. Phil Bryant said he and his wife “join all Mississippians … in mourning the death of our two police officers in Hattiesburg.”

“This should remind us to thank all law enforcement for their unwavering service to protect and serve,” Bryant, a former deputy sheriff, said in a statement. “May God keep them all in the hollow of his hand.”