THE WOMAN'S 5-foot-3, 100-pound nude body, beaten and bruised, with her bra strap tightly wrapped around her neck, was found behind her 4th Street building in a lot strewn with rubble and dog waste, a city prosecutor said Tuesday.

"Tiny, small, petite but so vulnerable. Perfect prey," Assistant District Attorney Richard Sax said of Sabina Rose O'Donnell during his opening statement.

Sax told the jurors that Donte Johnson — the 20-year-old high-school dropout accused of abducting, raping and murdering the popular Northern Liberties waitress — stalked O'Donnell along Girard Avenue, as she rode a borrowed bicycle home in the early morning of June 2, 2010, because "he knew he could dominate, overwhelm and control" her.

But as Johnson rode his own bicycle behind hers, Sax said, he was recorded on store video cameras, which the jury will be shown. Johnson also left behind his DNA, "all over her, inside of her," Sax said. "He destroyed her," the prosecutor said, eliciting muffled cries from the victim's mother, Rachel O'Donnell, and other relatives and friends.

Johnson, of 11th Street near Poplar, began the trial by standing and pleading not guilty to every charge lodged against him, including murder and rape. If convicted of first-degree murder, he will receive a mandatory life sentence without parole.

"This is not a case of first-degree murder," said defense attorney Lee Mandell, who cautioned the jurors not to rush to judgment. "The people who test for DNA are people like us. They are human beings. Like all human beings, they are capable of making mistakes."

He said that the testimony of Gerald Cooke, a forensic psychologist who gave the defendant numerous tests, will help the jury determine if Johnson was capable of making a voluntary confession to police, which the prosecution alleges he did.

Johnson was likely born with brain damage, has a low IQ of 73, functions at the intelligence level of an 11- or 12-year-old child and has abused marijuana and alcohol for years, Cooke said during a motion hearing on Monday.

Mandell also asked the jurors not to let sympathy for the victim's family "interfere with your ability to make the appropriate decision."

Before Common Pleas Judge Glenn B. Bronson let the jury go home for the day, Sax called his first witness, the victim's mother.

Rachel O'Donnell, her face washed in pain, recalled speaking with her daughter by phone for the last time the day before she was slain. The last time she saw her daughter was that Mother's Day.

"She took me out to lunch. She was perfect and healthy," Rachel O'Donnell said, fighting back tears. n

Mensah M. Dean, contact him at 215-568-8278 or deanm@philly.com