SAN DIEGO (KGTV) - The suspect in the shooting death of a man near the 24 Hour Fitness in the Midway area is an undocumented immigrant with a prior immigration violation, according to law enforcement sources.

San Diego Police arrived at the rear parking lot of the gym at 3675 Midway Drive February 25 to find Alexander Mazin, 27, suffering from a gunshot wound to the torso. He died at the scene.

After the shooting, officers surrounded an apartment at 30th St and Upas in North Park. The standoff ended hours later without an arrest.

RELATED: Parents of Midway shooting victim describe son's life, violent murder

Law enforcement sources told 10News the suspect, Ernesto Castellanos Martinez, had a prior “voluntary departure” agreement which meant he had been asked to leave the country after an immigration conviction in 2004. He left, but eventually made it back into the U.S.

Mazin’s family said Castellanos had previously been in a relationship with Mazin’s girlfriend of three months.

Two weeks before the shooting, Castellanos had attacked the woman while she was working out with Mazin at a gym, Mazin’s parents said.

RELATED: Police release pictures of Midway District homicide suspect

Their son’s death has galvanized their support for President Donald Trump’s plan to build a wall across the southern border.

“I want President Trump to know about this,” Jeffrey Mazin told 10News. “I want him to be aware there was a true patriot, a wonderful human being that was an exemplary citizen that was lost because of this problem with our border.”

But framing their son’s death as an immigration problem worries Dulce Garcia, an immigration attorney and an undocumented immigrant herself.

She has protection from deportation through Deferred Action for Childhood Arrivals (DACA). To her, immigration status should be irrelevant in this case.

“Someone is going to commit a crime whether they are undocumented here or not,” she argues.

Garcia said her reason is that people like herself, who are otherwise law-abiding members of society, are put at higher risk for deportation when they get grouped in with criminal fugitives.

“That’s the truly terrifying part for me because I don’t think that’s American. I don’t think we as a nation agree to paint any group based on what one person’s actions did,” said Garcia.

Castellanos remains at large. The victim’s family said police believe he may have fled to Mexico.

A reward has been issued for his arrest. Anyone with information can report tips anonymously to San Diego Crime Stoppers.