A 32-year-old man has been found guilty of first degree murder of a trans woman in the US state of Colorado.

For the first time a 2005 law that added protections for people based on sexual orientation, including “transgender status,” to the state’s “bias-motivated crimes” statute, was used.

Allen Andrade was sentenced to life in prison without parole, the mandatory penalty for first-degree murder in the state.

The jury took just two hours to reach their verdict that he murdered Angie Zapata. He bear the 18-year-old to death in her apartment.

The pair had met on a dating website and spent the night together. He claimed he flew into a rage when he “discovered” she had been born male.

Her body was found hidden under a blanket at her apartment in Greeley by her sister.

Ms Zapata began living as a woman when she was 16 and had wanted to dress in a feminine style since the age of seven.

After Andrade was sentenced his victim’s mother said:

“The one thing he can never take away is the love and memories that me and my children will have of my baby, my beautiful, beautiful baby.”

Andrande told police he had hit Ms Zapata twice in the head with a fire extinguisher and thought he had “killed it” before hitting her again as she tried to stand up.

He then struck her a third time with the fire extinguisher and also took her purse, keys and phone before fleeing in her 2003 Chrysler PT Cruiser.