Family and friends were also present to pay their respects at Morraine Valley Church in Palos Heights. Among them was the widow of Kyle Deatherage, another trooper who died in the line of duty just four months ago.
"I think it's a sign of survivorship that they too were in that position and went through it and can now show strength in her time of need," said Lt. Mark Karczewski, Illinois State Police.
Mourners were especially touched by a deepy personal tribute from Sauter's 17-year-old brother.
"His younger brother has shared with me that he wants to become an Illinois state trooper as well so he can make his brother proud," said Hiram Grau, Illinois State Police director.
The 28-year-old from Vernon Hills was pronounced dead early Friday after a semi-truck hit his squad car as it idled along the side of the road.
"He had the brightest, warmest smile anybody could ever have," said Trooper Raymond Kurut, a friend and colleague of Sauter's. "Most of us out here put our lives in the line every day...Jim was dedicated to his duty to protect the people, and that means possibly putting yourself in danger."
Sauter was a pilot who recently left the State Police Air Unit because he wanted to engage in more hands-on policing on the ground.
"We have a term in the state police called 'the road dog.' Jim loved more than anything else being a road dog out there. Jim was one of those people who would want a canine, a motorcycle, a plane, all of it... to serve land to sea," said Kurut.
Sources say the trucker appears to have been speeding. There were no skid marks, a sign the trucker did not brake before the impact. Police say the truck was also in a lane restricted for cars.
Sauter became a trooper in 2008. His funeral will be Tuesday morning.