BRENTWOOD, N.Y. — These days, Evelyn Rodriguez always carries her blue clipboard, jotting down notes when inspiration or anxiety strikes. It has been her constant companion in the 10 months since her 16-year-old daughter, Kayla Cuevas, was killed by members of the transnational MS-13 gang.

She plans to carry it with her, too, on Friday, when she meets with President Trump, who is coming to Suffolk Community College in this working-class Long Island town after the recent arrests of MS-13 members for the murders of four young Latino boys. Authorities say that the wave of gang violence resulting in 17 murders in the county since 2016 has been fueled in part by illegal immigration of young people; many of the victims have also been immigrants or the children of immigrants.

Some politicians and activists have denounced Mr. Trump’s visit, saying that it will encourage the targeting of undocumented immigrants. But Ms. Rodriguez, a fierce wisp of a woman who grew up in Puerto Rico and the South Bronx, sees an opportunity.

“I’m going to break it down for him,” she said. “‘Look, I’m not here to tell you how to do your job; I’m not here to talk about immigration.’” Ms. Rodriguez wholeheartedly agrees with the president that immigrants who are criminals should not be coming into the country, nor should they be allowed to enroll in the local schools.