The mission of the Los Angeles Police Department is to protect and serve.
But since 1979, officers have also vowed not to stop anyone solely because a person appeared to be an undocumented immigrant.
"If you're in the crime-fighting business, you can't have people too afraid to be witnesses or too afraid to report crime," says Connie Rice, a civil rights attorney and longtime LAPD watchdog (Disclosure: she is also on the board of trustees for SCPR).
The practice comes from a policy known as Special Order 40, instituted by then-L.A. Police Chief Daryl Gates.
A surge of immigrants came to Los Angeles in the late 1970s, and Gates believed that to deal with crimes like gang violence, murders and robberies, he needed the community – even if they were undocumented – to work with officers.
"There's a lot of discretion in policing," says Rice. "There are many, many laws that are not enforced for smarter strategies that are crime-fighting strategies."
Police officers were instructed not to stop and frisk anyone because they might be undocumented.
However, the LAPD could still involve federal officials if someone committed a crime.
"If there's an established gang member who's in jail for violent offenses and they were previously deported, I know for a fact that that person will be held and [immigration officials] will be notified," says Rice.*
The decades-old practice has the full backing of current L.A. Police Chief Charlie Beck, as well as elected officials in City Hall.
"They've reaffirmed it at least four times since Nov. 8th, since the election," says Rice. "It's an important signal to send."
But over the years, many have pressed the city to drop the policy.
In 2008, for example, 17-year-old Jamiel Shaw was shot and killed by Pedro Espinoza, a gang member and undocumented immigrant.
Shaw's family argued that if Special Order 40 didn't exist, then Espinoza never would have been in America to begin with or would have been deported earlier. His parents even took that message on the campaign trail while supporting Donald Trump's presidential run.
But Rice argues dropping the practice would do far more harm.
"The status of that gang member may be a red herring," she says. ""If you deported every undocumented gang member, you would still have scores of thousands of gang members who still engage in the same activities and posing the same danger to their neighbors."
And despite the hard line President Trump has taken on illegal immigration, Rice believes that local officials will hold firm to Special Order 40.
* NOTE: In the interview, Connie Rice referred to Immigration and Naturalization Service, which used to oversee illegal immigration offenses. That agency ceased to exist in 2003, and those duties are now handled by Immigration and Customs Enforcement.