Police officers in New York City are throwing their badges behind a polarizing figure-Colin Kaepernick.
"The group of around 75 wore T-shirts that read, "#imwithkap", though City Council member Jumaane Williams wore a Kaepernick jersey.
Retired officer Frank Serpico, who became famous for standing against police corruption, was among the policemen wearing '#imwithkap' shirts in Brooklyn.
Kaepernick, who opted out of his 49ers contract after last season, remains unsigned.
The 29-year-old Kaepernick is now unable to find work with an NFL team after drawing controversy last year when he refused to stand for the national anthem before games. Al Pacino portrayed him in the film "Serpico".
He admitted not being a football fan, but said he felt it was important to support Kaepernick for his stance.
'He's trying to hold up this government up to our founding fathers, ' Serpico added.
He said it was a protest against oppression of black people.
Serpico uncovered widespread corruption in the NYPD while working undercover in the late 1960s and early 1970s.
"The way he's being railroaded for speaking the obvious truth, this is not what America was founded on", NYPD Sergeant Edwin Raymond said at the rally.
The NAACP chapter in Atlanta is calling for all football fans to boycott NFL games by not watching those contests until a team signs Kaepernick.
Serpico has become well-known for his activism regarding police brutality, and on Saturday he took a knee and raised a fist with his fellow brothers in blue.
"As members of law enforcement, we can confirm that the issues that he is saying exist in policing and throughout the criminal justice system".
"If Mr. Kaepernick is not allowed to pursue his career, then on September the 17th, at 5 o'clock, we are going to have the world's largest tailgate, and that tailgate will not go into Mercedes-Benz Stadium", Griggs said, according to CBSSports.com.
Kaepernick has not made a statement on his current free agency since he stepped away from the 49ers in March, but the rumors coming out of his camp are that he still wants to play quarterback in the NFL.