(CBS) — Family, friends and colleagues said goodbye Monday to slain Fox Lake Police Lt. Charles Joseph Gliniewicz.

Not one ounce of respect was spared as a community and a nation said goodbye to an officer affectionately known as “G.I. Joe,” who was found fatally shot last Tuesday after telling co-workers he was pursuing three suspects.

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“When we were growing up, we all knew Joe was a hero, but now the nation knows he’s a hero,” the officer’s brother, Michael Gliniewicz, told mourners who filled Antioch High School.

Many people who attended never even knew the fallen officer.

“We all wear the same badge and do the same job,” says New York Police Officer Mike Nicoletti, who traveled cross-country to pay his respects. “When one of us gets hurt, we all get hurt.”

After the funeral, a procession began making its way through Fox Lake on its way to Hillside East Cemetery in Antioch, where the more than 30-year veteran and father of four was to be buried in full military honors.

CBS 2’s Vince Gerasole reports it was majestic and emotional Lt. Gliniewicz’ flag draped casket was escorted into his old high school. Leading the way was his son in the Army.

“We are all brothers in blue, we all bond together so when one of ours falls we all fall,” said village of Oak Hills Police Chief Peter Goldman.

Not far behind, the lieutenant’s widow surrounded by a seemingly endless gathering of officers.

“It’s just one big family,” said Amtrack Railroad Police Officer John Niles. “We are here for each other, through the good and through the bad.”

They came from as far away as Florida but their message was mostly the same.

“I think it impacts everybody,” said Round Lake Beach Police Officer Keith Arabel. “It’s a big blue family and everyone feels it when something like this happens.”

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Among those filing past his casket were those who knew him well.

“As a friend I owed it to him because he was a service brother, he was a law enforcement officer” said Dan Lyon.

Antioch High School was surrounded by flags in Gliniewicz’ honor, and beside them people like Joan Church who never met the lieutenant, but made a point to be here with signs of support.

“I think the police lay their life on the line every time they step out of the house and I just want to show support for that,” Church said.

“The community support throughout these last very trying days has been just amazing, unbelievable,” said Lake County Sheriff’s Detective Chris Covelli. “The love shown for the Gliniewicz’ family has been tremendous.”

It was estimated as many as 5,000 people participated in the procession or the funeral.

Sunday, complete strangers, volunteers, and people who only knew Gliniewicz in passing came together to clear out weeds and then decorate stretches of the 18-mile procession his hearse was to pass. They wrapped posts in purple and taping down the memorial colors of black and blue. Some turned out after hearing about the chance to pitch in through Facebook and social media.

“Lieutenant Joe touched so many lives, even those that never knew him or met him and just knowing that he has protected out community for 32 years, that’s why people are doing this,” said Fox Lake resident Carol Martin.

BMO Harris Bank has created a memorial fund for Gliniewicz’ family. You can make a donation at any BMO Harris Bank branch. Also, it is expected to be especially hot and humid today, firefighters will have extra ambulances along the route in case anyone needs medical attention from the heat.

Meanwhile, investigators are still searching for the people who shot and killed the officer.

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Police are increasing patrols through the holiday weekend to search for the killers. Investigators are also reviewing security and traffic camera video and following up on information from a tipline. A $50,000 reward has been offered for information leading to the capture of the suspects.