Prosecutors in the first-degree murder trial of the man accused of killing a transgender woman last July are preparing their closing arguments in a Colorado courtroom today. Jurors are expected to begin deliberations this afternoon, reports CNN's In Session.

Angie Zapata was eighteen last summer when she met Allen Ray Andrade, 32, on, a social networking site run through mobile phones. On July 14, 2008, she borrowed her sister's PT Cruiser and traveled more than 50 miles to pick up Andrade and bring him to her tiny Greeley, Colorado apartment, where the pair shared several days together.

Andrade has confessed to killing Zapata, formerly known as Justin Zapata, in a fit of rage when he confronted her about her sexuality. He beat her first with his fists and then with a fire extinguisher and beat her a second time when he realized she wasn't quite dead, police allege.

Defense attorneys have mounted a trans-panic defense for Andrade they hope will minimize his sentence from life in prison down to possibly 25 years. They say Andrade killed Zapata because he was “deceived.”

“This is not about judgment of lifestyle,” Martin said in opening remarks. “This case is about a deception and the reaction to that deception.”

But prosecutors, who have also charged Andrade with a hate crime, disagree.

“This was not a snap decision,” Prosecutor Brandi Nieto told jurors. “The defendant knew for approximately 36 hours that Angie was biologically male.”

Zapata self-identified as a woman as early as 2004, jurors learned. Nieto told jurors that the day before she was killed, Andrade accompanied Zapata to municipal court to respond to a traffic ticket issued under the name Justin Zapata. And, Nieto said, if Andrade didn't know before then that Zapata was transgender, then he certainly found out at the courthouse.

The trial opened with gruesome photos of the victim and the murder scene: Zapata lying supine in her apartment living room, dressed in black plants and a white shirt; a photo of four forty-ounce Budwiser bottles, stacked neatly in the sink; another of a bottle of rum and a bottle of vodka on top of the fridge; and a blood-stained blanket and a pink vibrator on the floor next to Zapata's bludgeoned body.

Jurors also heard taped jailhouse calls between Andrade, a former girlfriend and a current girlfriend.

Andrade told former girlfriend Angie Tyree, “It's not like I went up to a schoolteacher and shot her in the head ... or like I killed a law-abiding straight citizen.”

Felicia Mendoza and Andrade reconciled their on-again-off-again relationship in the days following Zapata's death. Andrade drove to her home the day he killed Zapata, in the PT Cruiser. He told her he bought the car from a co-worker and showered her with roses he had bought and two purses he had stolen from Zapata's apartment.

Andrade was arrested on July 30, sitting outside Mendoza's home in the PT Cruiser.

An emotional conversation between the pair where they discuss the murder was played for jurors, “It was a mistake,” Andrade told her, “... somebody died ... I met this female; at least I thought it was ... I just snapped.”

On the final day of testimony, lab agents said they found Andrade's DNA on three items: a cigarette butt, one of the purses Andrade gave Mendoza, and the pink vibrator.

Sarah Lewis, a lab agent with the Colorado Bureau of Investigation, testified that a high level of Andrade's DNA was found on the vibrator; levels found in blood or saliva. Nieto asked if the sample is consistent with DNA found inside of someone's rectum. Lewis answered yes.

Seven members of Zapata's family and friends testified.

“I worried about her all the time” over taunts Angie endured since she was a little boy, Angie's sister Monica said. After not hearing from Angie for several days, she went to her apartment, where she found her sister's bloody body.

Andrade has decided not to testify on his own behalf.