Katie DeRosier remembers her husband, Justin, as “the type of dad a new mom and myself and child would dream to have.”

Following the birth of his daughter, Lily, late last year, the sheriff’s deputy often would bring her into the headquarters of Washington State’s Cowlitz County Sheriff’s Office and proudly show her around to his colleagues, they recalled.

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“As a father he was so excited, he always wanted to be a dad, and when we found out [I was] pregnant it was awesome,” Katie DeRosier told Fox News. “He was the best support for all of that, he was very hands-on."

Justin DeRosier, an officer whom Katie says “just wanted to do his best and make a difference," was killed April 14 after responding to a report of a disabled vehicle blocking a road near Kalama. Officials say DeRosier was hit with gunfire when he showed up at the scene and later died during surgery. The man who police said targeted him eventually was tracked down by cops and killed in a shootout.

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Since then, Katie DeRosier says there has been an “overwhelming” display of support for her and her family, with “cards and letters from literally every state making this nightmare a little easier to get through."

“It’s comforting to know that much support is out there for, not just my family, but for law enforcement,” she said.

The 29-year-old -- who served as a patrol deputy, SWAT officer and boat operator during his police career -- was described by Cowlitz County Undersheriff Darren Ullman as being “like one of my kids.”

Ullman told Fox News he helped coach DeRosier in tee-ball, and that DeRossier and Ullman's son grew up together – at one point both attending Washington State University.

There, Ullman says, he saw DeRosier become a “protector” – a personality trait he would later display as an officer.

“He was in a fraternity and he would stay sober and drive everyone around...he had that sense of responsibility from the early days,” Ullman said. He emphasized DeRosier “always was having a great time,” yet “knew what was right and what was wrong.”

DeRosier graduated from the university with a criminal justice degree and when he joined the Cowlitz County Sheriff’s Office – located less than an hour’s drive north of Portland, Oregon – he was still hungry to keep learning.

“I was constantly denying training requests from him,” Ullman remembers. “He wanted to go to every training, every event -- he couldn’t get enough."

“He was a ball of fire, a bull in a china shop basically, a big guy, we had to reel him back,” Ullman said. “But we knew there was something good about him.”

One of his former supervisors says throughout DeRosier’s three years with the department, he was the “ultimate team player."

“Everybody that knew him liked him,” Chief Criminal Deputy Troy Brightbill told Fox News. “If he had the slightest hint you needed help with something on duty or off duty he was going to show up, he was going to help you.”

Brightbill says DeRosier also was “very diligent about following up with victims on his cases,” making sure no one felt forgotten.

Outside of work, DeRosier waterskied and rode a dirt bike. He also was working on restoring a truck.

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But ultimately, Ullman said, DeRosier was the “prototype of what we wanted as a cop."

“Young, smart, not afraid to do what is right. Vulnerable. He wasn’t perfect, he was human,” Ullman said. “And that’s all that we need more than anything in police work. He liked to have fun, but at the same time worked his ass off and was just a good human."