"All of a sudden, the guys would get close and ask me, 'Who's that, Monica?'" said Angie's sister, Monica Zapata of Brighton, describing the reaction of her co-workers, including some who had met her brother Justin before Justin became Angie.

"She's pretty, huh?" Monica Zapata would tease them.

Allen Andrade, 32, of Thornton, went on trial Tuesday in Angie Zapata's death in July. He's accused of beating her to death with a fire extinguisher after spending the night at her Greeley apartment and then finding out she was biologically male. The two had met through a mobile networking site.

About 500 potential jurors have been called for questioning in the case which has received nationwide coverage, including CourtTV.

Andrade faces several charges, including first-degree murder and a bias-motivated crime, which could add three years to his prison sentence if convicted. He's being held without bond at the Weld County Jail.

Nearly a year after her death, friends and family continue to cope with the loss of the 18-year-old Zapata, who grew up in Fort Lupton, a farming community of about 6,800 people, before moving to Greeley to help her sister Monica care for her kids. Monica Zapata and 20-year-old Rochelle Camacho, Angie Zapata's friend since kindergarten, recalled Angie's life and her struggle with dating as a transgender woman.

Justin Zapata preferred to gel his hair in a girl's hairstyle and grow out his fingernails, even at a young age.

"She wore a bra to second grade stuffed with a hard paper towel," said Camacho. "We were on the playground, and I took some of the paper towel out, and asked what is he doing. And from then on, I knew."

Camacho was 13 when she first saw Justin Zapata dress as Angie. Angie wore jeans, a tight top and a pullover to hide her flat chest for a walk around a Fort Lupton neighborhood. A male friend didn't recognize her.

She started living as a girl at age 16.

"I couldn't even take Angie to the laundry mat because she would draw a lot of attention," Monica Zapata said. "Even the girls would go up to her and be all, 'How do you do your makeup like that?'"

There were also stares and whispers from strangers and a long line of heterosexual suitors disappointed at the news that she was biologically male.

"I heard her conversations. 'Hey, before we go any further, I have something to tell you.' A lot of times I would see she would be on the phone and she'd be, 'Hello? Hello?" said Monica Zapata. "Some would hang up on her. Other times, some would be asking questions."

Angie Zapata had several relationships, including one with a heterosexual man that lasted four months, Monica Zapata said. But that relationship ended the way most did -- with the boyfriend dating a biological woman.

"They'd say, 'I'd thought I could, but I can't,'" recalled Monica Zapata. "She would cry."

Andrade was arrested July 30 and was driving Angie Zapata's car, nearly two weeks after her body was discovered by her sister in her apartment on July 17.

Andrade told investigators that Zapata had performed oral sex on him but wouldn't let him touch her, according to the affidavit. He said he also spent the night at Zapata's apartment, but in separate beds. The next day, Zapata left Andrade alone in her apartment, and Andrade noticed several photographs that led him to question Zapata's gender, investigators said.

Andrade confronted Zapata when she got back. Zapata answered: "I am all woman."

He grabbed Zapata's crotch area, felt male genitalia and became angry, the affidavit states. He took a fire extinguisher off a shelf and struck Zapata twice in the head, telling investigators he thought he "killed it."

Andrade told investigators he covered Zapata with a blanket and started gathering evidence he thought might link him to the crime when he heard gurgling sounds and noticed Zapata was sitting up. That's when he beat her again and again with his fists, prosecutors said.

A judge last month threw out part of Andrade's confession, saying police didn't honor his request to remain silent 39 minutes into his interrogation. Tape-recorded jail calls in which Andrade allegedly told his girlfriend that he "snapped" will be allowed by District Judge Marcelo Kopcow during the trial.

In the calls, he allegedly said he was out of control and out of his mind. The calls were laced with derogatory remarks about homosexuals, and when Andrade's girlfriend said that her cell phone was dying, he said that was "gay" and "gay things need to die," the Greeley Tribune reported.

Andrade is believed to be the first person tried for a hate crime under the sexual orientation section of Colorado's hate crime law, according to the New York and Los Angeles-based Gay & Lesbian Alliance Against Defamation, or GLAAD. Colorado is one of 11 states to have such designations in their laws, according to GLAAD.

State court officials say 70 felony hate crimes have been prosecuted since 2005, when the statutes were amended to include sexual orientation. But the law also covers crimes motivated by religion and race, and statistics aren't kept by group.

The Washington-based Human Rights Campaign hopes Zapata's case sheds light on the need to pass a bill introduced April 2 in the U.S. House that would add sexual orientation and gender identity to the federal hate crime law. Doing so would not only send a message that targeting people is wrong, it would allow the FBI and federal agencies to investigate such crimes, said Cristina Finch, senior counsel for the gay, lesbian, bisexual and transgender civil rights organization.

"It's part of the process of educating Americans that transgender Americans, they're just like the rest of us," Finch said. "They deserve the right to live just like the rest of us, free from discrimination and violence."