"We really might be looking at a new day under Sessions, and that has huge implications for how the federal government is going to treat violence that is absolutely rampant in the transgender community," said Jordan Woods, a University of Arkansas law professor who studies LGBT legal issues.
Sentencing in the Mississippi case is May 15. With a plea agreement in place, it's unlikely Sessions could change the strategy in this prosecution.
Joshua Vallum, an ex-convict and top-ranking gang member, faces life in prison without parole for killing 17-year-old Mercedes Williamson, who was born male but transitioned to a female. Prosecutors say Vallum, 29, and Williamson dated and that he killed his transgender girlfriend because he worried fellow gang members would discover their relationship and kill both of them because gay sex was strictly forbidden by the Latin Kings gang.
Attorney Dru Levasseur of the LGBT rights group Lambda Legal said supporters had a frustratingly long wait for the first federal hate crime prosecution involving a transgender person.
"We waited for many years for the government to finally deploy that law," Levasseur said.
Hate crimes have historically been a priority for the FBI and Justice Department. Investigations are typically initiated by the FBI and the attorney general doesn't need to sign off on each prosecution.
Six Democrats in Congress wrote to Sessions on March 10 to ask the Justice Department to investigate as hate crimes the deaths of seven transgender women this year, including another one in Mississippi.
The Justice Department declined comment.
Crimes motivated by a loathing of sexual orientation or race will often be prosecuted under state hate crime charges, but those vary. Mississippi, for example, doesn't include crimes against transgender people.
Usually defendants will also face charges such as assault or murder, but people are more likely to be convicted in federal court and can sometimes face longer sentences.
In Vallum's case, he pleaded guilty to murder in state court and was sentenced to life in prison, but with a chance of parole. He could get life in prison without parole for his federal guilty plea.
"There's a lot of variability in the willingness of state and local jurisdictions to prosecute," said Rebecca Stotzer, a University of Hawaii professor who has studied violence on LGBT people.
Vallum previously served time for a fake bomb threat at a church. While imprisoned, he joined the Latin Kings gang, going by the name King Chaos. After his release, Vallum met Williamson online and they dated for months in 2014.
In his defense, Vallum initially told sheriff's deputies and later The Sun Herald newspaper that he found out that Williamson had a penis on May 30, 2015 — moments before he killed her. He said he "blacked out" and doesn't remember the crime, a variation of what's known as a "gay panic" or "trans panic" defense.
Prosecutors doubted the claim, in part because the FBI found a cache of gay porn on Vallum's cellphone and because he was charged with indecent exposure in Alabama. Most significantly, Vallum didn't contest evidence in court that he long knew Williamson was transgender.
Federal prosecutor Julia Gegenheimer said during Vallum's plea hearing in December that he began planning to kill Williamson after a friend called him May 28 to say he'd discovered her identity.