SAN ANTONIO - The man who allegedly killed a veteran police officer in Texas on Tuesday during a domestic violence call is a 51-year-old Salvadoran with a criminal record who is present in the United States illegally, U.S. Customs and Immigration Enforcement said Wednesday.

Elmer Manzano was arrested after allegedly opening fire on officers at a Houston apartment complex, killing Sgt. Harold Preston, 65, a police commander who was weeks away from retirement.

In a statement, ICE said Manzano is a "convicted criminal alien who is unlawfully present in the U.S." and the agency has placed a detainer with county authorities seeking to take him into federal custody.

The killing of a veteran police commander by an immigrant living in the country illegally is likely to fuel the Trump administration's campaign-trail attacks on "sanctuary" jurisdictions that limit cooperation with ICE.

Houston is not a sanctuary city, but its police department does not fully cooperate with the agency, an approach that Police Chief Art Acevedo has defended as a way to balance public safety with a need to preserve trust between local officers and the city's immigrant communities.

Acevedo said Preston, a 41-year veteran, was "a hero" killed while responding to a domestic disturbance call at Manzano's apartment Tuesday morning. Another officer, Courtney Waller, was wounded in the incident while responding to the call. Manzano and Manzano's 14-year-old son were injured in the exchange of gunfire.

ICE officials and Department of Homeland Security leaders have launched a campaign of targeted arrests in cities with sanctuary policies in recent weeks, taking nearly 300 into custody. ICE has put up billboards in the Philadelphia area featuring the mug shots of immigrants wanted by the agency who were previously released by local authorities.

Houston is not one of the cities included in the campaign, which ICE calls "Operation Rise."

Donald Trump powered his 2016 run for office with depictions of immigrants as dangerous criminals, promising millions of deportations and a giant border wall to keep them out of the country. ICE statistics show far fewer deportations during Trump's first term than President Barack Obama's, in part because sanctuary policies have made the agency's work more difficult in cities with large immigrant populations, such as Los Angeles, Chicago and New York.

High-profile crimes and killings by immigrants have been a staple of Trump's messaging dating back to his first run for office, following the 2015 shooting death of Kate Steinle in San Francisco, a case that galvanized immigration hard-liners. A previously deported Mexican man was charged with Steinle's killing but was later acquitted, and a gun-related conviction in the case was overturned on appeal.

Early in his administration, Trump created a special office inside DHS, Victims of Immigration Crime Engagement (VOICE), and the president featured the family members of those victims at State of the Union addresses.

According to Acevedo, Preston, Waller and another officer spoke to Manzano's estranged wife in a parking lot outside of the Houston apartment building on Tuesday morning before going upstairs to speak with Manzano. She wanted to remove her things from the apartment, but Manzano had locked the door. After unlocking the door, the man's 14-year-old son warned officers that his father had a gun.

The teenager opened the door, and Manzano opened fire, police said, striking Preston in the head. He died hours later at a hospital.

Preston's family, including his fiancee, ex-wife, 23-year-old daughter and elderly parents were able to come to his bedside before the officer died, Acevedo said.

"I'm not calling him a hero because of the way he died today, but he is a hero," Acevedo said.

Charles McClelland Jr., the former Houston police chief, said his friend Preston was raised in Houston's tough Third Ward neighborhood. Preston graduated from Jack Yates high school - the same school George Floyd later attended.

"He was just a good son and good human being, and that combination made him a good police officer," McClelland said. "The Houston police department didn't make Harold Preston who he was. His upbringing, strong faith and his parenting, that's what made Harold Preston into a good cop."

Preston recently called McClelland, who also served four decades as an officer, to ask him how retirement was going. Preston had been contemplating his own departure but still relished so many parts of the job. He was caring for his two elderly parents at home, both of whom were in delicate health, friends said.

"He loved serving his community, and in our last conversation, he expressed he still enjoyed doing what he was doing," McClelland said. "It's a tremendous loss. What's gone is a man, an African American man, who wore the uniform in a way that little kids could look up to and aspire to be. He's the perfect example for his community - I mean who gives that type of commitment? 41 years? He beat me by one."

Houston Police Officer's Union President Joe Gamaldi said Preston was two weeks from leaving and that staff had been compiling a photo collage for his retirement ceremony.

During the disturbance call that took his life, Preston was not required to be on scene. There were two officers already engaged in the situation, but the sergeant was known for running his own calls, backing up his officers and helping instead of just supervising from afar, McClelland said.

"He cared enough about his officers that he thought it was important that he go over there and supervise that scene to make sure everything went right," McClelland said. "He was being proactive in his supervision and management of his troops."

Acevedo said police were called twice to Manzano's residence during the past weekend in response to domestic disturbance calls. Manzano has a lengthy criminal record that includes assault and domestic violence convictions, according to police records. But the arrests and convictions occurred between 1994 and 2002, years before the sanctuary city movement to limit local-level collaboration with ICE.

Acevedo has long walked a tightrope on immigration-related policing matters. The chief has opposed a Texas law banning "sanctuary cities," and his department historically has refrained from engaging in immigration enforcement. As president of the Major Cities Chiefs Association, he has issued statements saying he would not shield anyone who has committed a crime or inflicted harm on the community. In that role, he has pushed for meetings with the Department of Homeland Security to work out solutions, including the vexing work of determining which ICE-issued detainers are valid or present liabilities to local departments.

Texas jurisdictions - including Harris County, the third-largest in the country - have been among the most compliant with ICE detainers. Harris has one of the largest number of ICE arrests and transfers in the country, and the number of detainers issued there increased significantly during the Trump administration, according to Syracuse University's tracking database.

A new report by a Stanford researcher published this week examining federal data found no increase in crime between 2010 and 2015 in jurisdictions that adopted sanctuary policies, despite the administration's efforts to highlight violence incidents involving immigrants.