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Jacob Keltner, his father Howard said, “wanted to be a soldier or policeman since he could talk.”

From a young age, Keltner – who would go on to serve 13 years with Illinois’ McHenry County Sheriff’s Office – demonstrated some of the values that defined his later career in law enforcement.

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His mother Helen told Fox News she remembered a time in middle school when other children were giving Jacob a difficult time and Howard instructed him to hit back if things got physical.

Jacob’s response?

“He said ‘No, I can’t do that,'” Helen Keltner recalled.

Becki Keltner says Jacob "loved his family above everything" and "cared about everyone." He is pictured here playing a board game with his two children, Caleb, far left, and Carson, center.

Becki Keltner says Jacob "loved his family above everything" and "cared about everyone." He is pictured here playing a board game with his two children, Caleb, far left, and Carson, center. (Courtesy Becki Keltner)

“He said ‘I never want my teachers to be disappointed in me and they would be very disappointed in me if I punched somebody and that’s not what I’m supposed to do,'” she added. “He always wanted to appear respectful.”

In his adult life, Keltner served in a variety of positions at the McHenry County Sheriff’s Office. He started working in patrol before becoming a detective, then switched over to a narcotics unit. Eventually, he became a member of the U.S. Marshals Service Great Lakes Regional Fugitive Task Force.

“He worked extra hours on a daily basis, and where a lot of people would put stuff off, he was ‘go go go’ all the time,” Sgt. Dan Kramer said.

Jacob Keltner 'loved to try adventurous things,' his wife Becki tells Fox News. 'We went hiking, white water rafting, zip-lining, boating, camping, and took the kids to water parks,' she says. 'He loved to ride his bike and exercise to release the stress from his job and we spend countless hours in the pool together with all our friends and family.'

Jacob Keltner 'loved to try adventurous things,' his wife Becki tells Fox News. 'We went hiking, white water rafting, zip-lining, boating, camping, and took the kids to water parks,' she says. 'He loved to ride his bike and exercise to release the stress from his job and we spend countless hours in the pool together with all our friends and family.' (Courtesy Becki Keltner)

But Kramer remembers March 7 – the day Keltner was shot and killed in the line of duty -- as being the “worst day I have ever experienced in my life.”

His fugitive apprehension unit was working with a U.S. Marshals Fugitive Task Force team to arrest a suspect at a hotel in Rockford, Ill., when Keltner was hit by gunfire.

Jacob Keltner, who lived to be 35, served numerous positions within the McHenry County Sheriff's Office.

Jacob Keltner, who lived to be 35, served numerous positions within the McHenry County Sheriff's Office. (Courtesy Becki Keltner)

Hours later, after a police chase, the suspect was in custody. But Keltner, an officer who Kramer told Fox News “did his job better than almost anyone else I know," succumbed to his injuries at a local hospital.

“He was the last guy you think would get caught, too, since he was so good,” Kramer said.

In an emotional letter written by his wife, Becki, following Keltner’s death, she described March 7 as the day she “received the one phone call every police officer’s wife has nightmares about, only this time the nightmare is real."

“Now I find myself a 33-year-old widow, mother of two young boys who no longer have their daddy,” she wrote. “It feels unreal. It’s unfair. I have screamed. I have cried.”

Jacob Keltner, shown here as a boy, played in Little League. Becki tells Fox News that the weekend before Jacob died, he took Caleb to a baseball clinic in preparation for his son’s first Little League season and took him out shopping for gear afterward. Jacob purchased Caleb a Chicago Cubs hat and he continues to wear it ‘all the time,’ Becki says. She has attended all of Caleb’s practices and games this season, but she says opening day was ‘so hard for me’ as her son ‘should have been able to have his dad there.’ A loving father, she added, who ‘wanted to be there and help his son.’

Jacob Keltner, shown here as a boy, played in Little League. Becki tells Fox News that the weekend before Jacob died, he took Caleb to a baseball clinic in preparation for his son’s first Little League season and took him out shopping for gear afterward. Jacob purchased Caleb a Chicago Cubs hat and he continues to wear it ‘all the time,’ Becki says. She has attended all of Caleb’s practices and games this season, but she says opening day was ‘so hard for me’ as her son ‘should have been able to have his dad there.’ A loving father, she added, who ‘wanted to be there and help his son.’ (Courtesy Becki Keltner)

But she told Fox News the outpouring of support she received in the wake of her husband’s passing has been “nothing short of amazing.” She and Helen say they have received letters from local residents and strangers from around the country, with some sharing their personal phone numbers. Inside, the letters ask Keltner’s family to call if they ever need anything.

“I really wish that Jake had been there to see that in our community and just around the whole country,” Becki said.

Added Helen: “It gives you a new respect for humanity that not everyone has a bad attitude toward cops."

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Becki Keltner, in a letter published after her husband's death, said Jacob was an 'amazing dad who 'always found ways to have fun with the boys'. (Courtesy Becki Keltner)

Becki Keltner, in a letter published after her husband's death, said Jacob was an 'amazing dad who 'always found ways to have fun with the boys'. (Courtesy Becki Keltner)

Family, for Keltner, was a huge part of his life. He would build “giant forts in the basement” and “ziplines with rope” for his children, and often enjoyed swimming and having cookouts at his parents' house, Becki said. If she was having hard week herself, he would surprise her with things like secretly planned dates – always showing that he loved her.

“I think what I miss the most about him – he was always joking around, he would play practical jokes,” Becki said, noting that one of his favorites was sneaking up behind her and throwing party snaps to the ground.

In the wake of Keltner’s death, a memorial fund has been set up, shirts have been printed paying tribute to him, and at one point a local Texas Roadhouse restaurant set up a “Fallen Hero” table in his honor.

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Becki says when she is having a bad day or is feeling anxious about something, she thinks of Jacob 'telling me to keep going and that I can be brave and strong for the kids. "I am so lucky to have had him by my side for the last 15 years," she told Fox News. "We should have had the rest of our lives together. I had so much more love to give him."​​​​​​​

Becki says when she is having a bad day or is feeling anxious about something, she thinks of Jacob 'telling me to keep going and that I can be brave and strong for the kids. "I am so lucky to have had him by my side for the last 15 years," she told Fox News. "We should have had the rest of our lives together. I had so much more love to give him."​​​​​​​ (Courtesy Becki Keltner)

But Becki Keltner says she has at least one wish left to fulfill – to create “a world where we stop hating each other."

“We all need to show each other love,” she wrote in her letter. “Lift each other up. It’s the only way to stop this unconscionable madness.”