"He was a selfless guy, and he died doing a selfless thing," his brother-in-law, Brian Schoenbaechler, tells PEOPLE

Credit: Courtesy Wayne County Sheriff’s Office

According to Michael Krol’s brother-in-law, the 40-year-old officer – one of the five Dallas police officers fatally wounded by a sniper Thursday evening – was a kindhearted, quiet man who moved more than 1,000 miles to fulfill a lifelong goal of being a street cop.

Krol was working the Black Lives Matter protest in Dallas when a sniper opened fire. Twelve officers and two civilians were shot. Krol joined the police force in 2008, and previously spent four years working as a corrections officer in his home state of Michigan.

“He was a selfless guy, and he died doing a selfless thing,” his brother-in-law Brian Schoenbaechler, 44, a management consultant in Atlanta, tells PEOPLE. “I want people to know he wasn’t just a cop, but a man with a family and people who loved him.”

Schoenbaechler says most of Krol’s family members are still stunned to learn he’d been fatally shot while running towards the sounds of chaos.

“It’s just not real for us,” Schoenbaechler says. “He had a big extended family in the Detroit area and they are all coming through, bringing food, hugs and love.”

Before realizing his calling as a policeman, Krol, who was over 6 feet tall, was a standout basketball player for his high school team. After graduation, he worked for several years as a home healthcare worker.

“When I first met him, I was like, ‘Wow – that’s not something I could do personally … going to people’s homes taking care of them,” recalls Schoenbaechler. “He was a big guy with a big heart.”

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He later he took a job as a security guard at a Michigan hospital before landing a job with the Wayne County Sheriff’s Office.

“That was his first job with a badge and a uniform,” Schoenbaechler tells PEOPLE. “He had wanted to join Detroit’s police force but heard about this opportunity to join the police department in Dallas and so he moved there, by himself, not knowing anybody, just to fulfill his dream of becoming a cop.”

Krol never married, but is survived by his longtime girlfriend, Marie.

“I want people to honor him for his service,” Schoenbaechler explains. “He was a wonderful person. He wasn’t a drinker. He was a quiet, big guy … a man of few words, but when he did speak, it was usually something sarcastic or funny. He had this scowl on his face, because he’s from Detroit. But he was just super warm on the inside … warm and good.”