A Latin Kings gang member pleaded guilty on Wednesday to the first federal hate crime charge filed against the murderer of a transgender person by the U.S. Justice Department in American history.

According to unsealed court documents, Josh Vallum, 29, “willfully caused bodily injury” to 17-year-old Mercedes Williamson by tasing her, stabbing her multiple times in the head and body and striking her with a hammer, because of Williamson’s “actual and perceived gender identity.”

Though he had previously denied it, Josh Vallum confessed that he murdered Williams because of her gender identity.

The Department of Justice utilized the Matthew Shepard and James Byrd Jr. Hate Crimes Prevention Act — which passed in 2009 and expanded the 1969 federal hate-crime law to include crimes against those crimes motivated by a victim's gender, gender identity, sexual orientation or disability — to file the hate crime charge.

This is the first prosecution for targeting a transgender victim in U.S. history under the Hate Crimes Prevention Act.

Vallum had previously pleaded guilty to a Mississippi charge of murder by deliberate design, which earned him a life sentence with parole. He now faces an additional sentence of life without parole and up to $250,000 in fines when he attends his March 21 sentencing hearing.

As a policy, the National Center for Transgender Equality doesn’t applaud or condemn specific decisions to prosecute or convict or sentence any individual, but their policy director Harper Jean Tobin told NBC News that they were encouraged that crimes such as this one were being investigated.

"We are heartened whenever community leaders and public officials stand up for the dignity and the lives of transgender people and say that our lives are not disposable,” Tobin said. "We have seen that from the Justice Department."

However, Tobin added that the center is concerned whether the incoming administration will continue to defend transgender people and investigate these types of crimes. President-elect Donald Trump has appointed Sen. Jeff Sessions (R-AL), who voted against the Hate Crimes Prevention Act.

“We are very troubled that we won’t soon have a Justice Department that feels that way if we have an attorney general who doesn’t feel that way and voted against this Hate Crimes Prevention Act,” Tobin said.

The Latin Kings prohibit homosexuality, and prosecutors alleged that Vallum killed Williamson to hide the fact that he had maintained a sexual relationship with her.

For members of the transgender community, the specifics of this case are all too familiar.

“In a case like this one, it seems that sometimes people believe the stain of being associated with a transgender person is so intense that someone decides to kill them,” Tobin said. “The stigma facing transgender people is literally deadly.”