After 57-year-old Ronald Clark cashed a check Friday afternoon, he got back in his van to head back to work. He had no idea someone was lurking in the back of the van, waiting to attack.

It would be the last drive Clark would make.

As Clark drove his van down Marietta Boulevard in northwest Atlanta, a man emerged from the back of the van and struck him with a hammer, according to Atlanta police. Investigators believe Clark fought back before he was shot by the suspect.

That suspect then left Clark and got into another vehicle with two men already inside, police said. Clark died after being transported to Grady Memorial Hospital.

Atlanta police said Tuesday that they want to find all three suspects who played a role in the attack. Robbery appears to be a motive, but it’s unknown how long the trio may have been planning the attack or if Clark was specifically targeted, according to Sgt. Greg Lyon.

Clark’s widow, Marilyn, spoke publicly for the first time Tuesday afternoon at Atlanta police headquarters. She asked for the public’s help in finding those responsible for her husband’s death.

“Ron was the air that I breathe,” Marilyn Clark said. “He was my best friend. We talked two or three times a day for 15 years.”

Investigators hope surveillance video, posted on YouTube, both from a business and a passing MARTA bus will help identify at least one of the suspects, police said Tuesday.

Detectives believe one of the suspects appears in surveillance video taken at a Marietta Boulevard business. That suspect is then seen getting into a black Jeep Cherokee, believed to be 2008 to 2010 model, Limited Edition with side panels, police said. The license place is obscured, preventing investigators from identifying the Jeep’s owner, Lyon said.

Anyone with information about the suspects is asked to contact Atlanta police or Crime Stoppers Atlanta at 404-577-8477.