A Latin Kings street gang member plead guilty today to the murder of transgender teenager and Alabama native Mercedes Williamson.

Josh Vallum's trial on the charge of murder by deliberate design in the 2015 beating death of Williamson was originally set for next week, the Sun Herald reported.

He was sentenced to life in prison.

Williamson, 17, of Theodore, Ala. was an aspiring cosmetologist.

The murder remains under investigation by the U.S. Department of Justice to determine whether the killing was a hate crime.

Vallum told police he used a hammer to beat Williamson to death after learning she had a penis. The incident occurred between May 30 and June 2, 2015, while they sat in Vallum's car on his father's property in George County, Miss.

Witnesses, however, say Vallum was in a sexual relationship with Williamson, and he knew Williamson was a transgender girl.

During testimony at a June 23 pre-trial hearing, Williamson's former roommate claimed Williamson spoke about how she and Vallum would be killed if the Latin Kings learned of their relationship.

Prosecutors claim Vallum's "fear of exposure" led him to kill Williamson.

Updated with guilty plea and sentence at 3:10 p.m.