WASHINGTON — The Justice Department has dispatched an experienced federal hate crimes lawyer to Iowa to help prosecute a man charged with murdering a transgender high school student in 2016, a highly unusual move that officials said was personally initiated by Attorney General Jeff Sessions.

In taking the step, Sessions, a staunch conservative, is sending a signal that he has made a priority of fighting violence against transgender people individually, even as he has rolled back legal protections for them collectively.

The Justice Department rarely assigns its lawyers to serve as local prosecutors, and only in cases in which they can provide expertise in areas that the federal government views as significant.

By doing so in this instance, Sessions put the weight of the government behind a small-city murder case with overtones of gender identity and sexuality.

Kedarie Johnson, a 16-year-old student in Burlington, Iowa, was shot to death in March 2016.

Family and friends told local newspapers that he was gay, identified as both male and female, and occasionally went by the name Kandicee. Christopher Perras, a Justice Department lawyer, will serve as a county prosecutor in the case, according to court documents filed Friday.

“This is just one example of the attorney general’s commitment to enforcing the laws enacted by Congress and to protecting the civil rights of all individuals,’’ said Devin O’Malley, a spokesman for the Justice Department.

Nine months into his tenure as the nation’s top law enforcement official, the nuances of Sessions’ civil rights policy are coming into focus.

As a senator from Alabama, Sessions had spoken out against same-sex marriage and voted against expanding federal hate crimes laws to protect transgender people, and civil rights groups were livid when President Donald Trump nominated him to be attorney general. They predicted he would reverse policies on discrimination, police abuses, and other areas.

In many ways, Sessions has fulfilled those predictions. He declared that the Justice Department no longer considered gay or transgender people to be protected from workplace discrimination and reversed a policy encouraging schools to let transgender students use bathrooms that fit their gender identities.

He abandoned objections to voter identification requirements in Texas and signaled that he would not try to force federal oversight on police departments suspected of abuses.

But he has also brought several hate crime cases, including one against a man accused of burning a mosque. He condemned white supremacist violence in Charlottesville, Va., far more forcefully than the president.

And he has vowed tough action against hate crimes, speaking aggressively in ways that few of his most ardent opponents could have predicted. He has tied enforcement of those crimes to his tough stance against violence, a cornerstone of his policies as attorney general.

“Hate crimes are violent crimes,’’ Sessions said in a speech in June, promising that the Justice Department will do more to combat violent crime.

He has publicly applauded aggressive hate crime prosecutions, including one in which a Mississippi man received a 49-year prison sentence in the death of a transgender woman. That case was brought in the final weeks of the Obama administration.

“No person should have to fear being violently attacked because of who they are, what they believe or how they worship,’’ Sessions said.

During the Obama administration, the Justice Department pushed the boundaries of civil rights, routinely arguing for a broad reading of the law.

Critics and supporters agree that Sessions is more likely to pursue civil rights matters in individual cases, rather than trying to address larger, systemic issues, as the Obama administration did.

He has promised to “punish any police conduct that violates civil rights,’’ for example, but is skeptical of efforts to force departmentwide overhauls. He supports prosecuting those who commit violence against transgender victims but opposes reading the law in a way that broadly extends discrimination protection for transgender people.