Angie Zapata in Greeley, CO

A Greeley transgender woman was apparently murdered this month because a man she met on the Internet became angry when he discovered she was biologically male.

The Weld District Attorney charged Allen Ray Andrade, 32, of Thornton with second-degree murder and aggravated motor vehicle theft Wednesday after Thornton police arrested him on traffic warrants and Greeley police arrested him thereafter on the murder charge. He was picked up while he was in the dead woman's car.

The news came as an incredible relief for Angie Zapata's sister, Monica Zapata.

"I thought they were never going to find him, honestly, I was doubting the police. I was doubting everybody. I just thought he was going to be out there forever," Monica Zapata said in an interview with Fox 31. "But when they called me and they told me I was the first one they called, it lifted away from me — that knot from your throat, like it was not there anymore."

An arrest affidavits shows Andrade told officers he met Angie Zapata on the Internet and they got together in Greeley. When he discovered Zapata was biologically male, he beat her to death with a fire extinguisher.

Zapata, who was born Justin Zapata, was a transgender woman who lived under the name Angie.