The clashes that longtime immigration advocate Martha Arevalo had with the Los Angeles County Sheriff’s Department under Jim McDonnell were years ago — but still fresh in her mind after this week’s election.

Under McDonnell, who was sheriff during Donald Trump’s first term as president, the department allowed federal immigration authorities to operate freely, targeting people for deportation in the nation’s largest jail system.

So as soon as Arevalo heard that McDonnell was selected for the LAPD chief’s job — with Trump returning to office and pledging to conduct mass immigration sweeps — she braced for another fight.

McDonnell and some of his supporters have defended his record with the Sheriff’s Department, saying his administration only handed over the most dangerous criminals to federal authorities, in keeping with the laws. He would not do so as chief, McDonnell has said, because department rules forbid it.

But Arevalo, executive director of CARECEN Los Angeles, is among those raising concerns about McDonnell’s record on immigration and pushing for stronger protections of the city’s diverse immigrant population. The incoming chief is scheduled to appear Friday before the City Council for confirmation, with his swearing set for Thursday.

“It is worrisome in L.A. where we are a city of immigrants, we choose someone to lead the Police Department that does not have a track record to care for, or be friendly, or even want to protect the immigrant community,” said Arevalo. “Maybe this was naive of us, or naive of me, but I never thought that the city and the mayor would chose somebody like McDonnell to be chief.”

The LAPD has long-standing policies that should prevent McDonnell — or any other chief — from cooperating closely with federal immigration authorities.

For more than 40 years, the LAPD has prohibited officers from questioning residents solely to determine their immigration status. After Trump’s first election in 2016, the department stepped up its efforts to foster trust and cooperation among undocumented people. Observers say that continued outreach has allowed the department to make significant strides in some communities that were long mistrustful of law enforcement.

The police force — once almost all white — has become more than half Latino, much like the ethnically diverse city it patrols. After the passage of a state law allowing police to hire immigrants brought to the country illegally as children, it also welcomed its first recruits who were so-called Dreamers.

But Arevalo said that days after Mayor Karen Bass selected McDonnell for the chief’s job in early October, she and other immigration advocates held a meeting with both officials and left “disappointed with the very weak answers that we received.”

“All he could really say is that he would follow the law and unfortunately we know that that does not necessarily guarantee protection,” Arevalo recalled of McDonnell.

McDonnell provided a similar response when he appeared before a council committee last last month and faced questions about his immigration record. He was noncommittal when asked whether he would support a sanctuary city ordinance being pushed by some community groups and several council members to shield some immigrants’ deportation, saying simply that he would follow the law.

Advocates for the immigrant community say that police encounters, already fraught with risk for the city’s undocumented population, will become even more problematic under the expected ramping up of enforcement under a second Trump administration. Minor violations such as a broken taillight or seat belt left unbuckled may lead to a ticket for an average motorist — but for someone who is undocumented it can have life-altering consequences.

During the first four years of the Trump presidency, police in L.A. and elsewhere reported decreases in reporting of even serious crimes such as domestic abuse, which some experts saw as a sign that people had become fearful of calling law enforcement.

“We saw it when McDonnell was sheriff, and families and victims will not call the police even if they are victims of domestic violence,” Arevalo said.

McDonnell has not granted interviews since being named LAPD chief. In 2017, he described himself to The Times as “not a Trump guy” and “not an anti-Trump guy.” He has been a registered Republican in the past, but said during his time as sheriff that he was no longer affiliated with a political party.

Maraky Alemseged, a local organizer with the Black Alliance for Just Immigration, said the concerns extend beyond the Latino community. A study by the organization found that people of African descent were disproportionately represented among people deported in recent years, Alemseged said, often because a low-level offense led to their detainment.

“When we talk about the police to deportation pipeline is a racial justice issue, this is exactly what we mean,” Alemseged said.

Other research has also shown that immigrants are less likely than U.S. citizens to commit violent crimes.

Alemseged and others have called on the City Council to reject McDonnell’s appointment; they plan to gather outside City hall on Friday to voice their opposition.

The department’s relatively tolerant posture toward undocumented people dates back to 1979, when then-Chief Daryl F. Gates responded to a wave of illegal immigration by trying to keep lines of communication open between officers and the communities they police.

Gates issued the policy known as Special Order 40, which prohibited officers from initiating contact with anyone for the sole purpose of learning their immigration status. Gates also prohibited arrests solely for violations of U.S. immigration law.

The department currently bars officers from inquiring about a place of birth when interviewing victims, witnesses or people who are temporarily detained. Previously, during arrests — but no longer — a suspect’s place of birth was recorded during fingerprinting and sent to an FBI database, which immigration authorities can access.

The LAPD also no longer transfers people with certain minor criminal convictions to the custody of Immigration and Customs Enforcement. Officers continue to hand over those wanted for signed federal warrants for serious or violent felonies, including for murder, rape, criminal threats, carjacking and arson.

During a presentation before the Police Commission in May, Cmdr. German Hurtado of the Professional Standards Bureau said that the department had not complied with any of the 631 “detainer” requests it had received last year from federal authorities to hold undocumented immigrants for possible deportation.

The department’s policies to protect undocumented people have faced repeated attacks both from factions within the LAPD as well as anti-immigration activists who say they give a free pass to criminals in the country illegally.

The department does, however, assign officers to scores of federal task forces, including one with Homeland Security Investigations dealing with “crime tourists” from South America who travel to the state on temporary 90-day visas and form burglary rings.