Christina Sirochman felt something was wrong when her dog sniffed out a woman's shirt and shorts in an overgrown lot on the edge of Northern Liberties where they often went for morning walks.

The sense of dread deepened as she saw lip gloss and makeup scattered around, and as her dog led her toward a patch of tall weeds behind a tree, she saw the partially hidden, nude body of a young woman on the ground. She put a hand on the woman's bloodied face and knew she was dead.

"It was like touching a piece of glass," she testified Wednesday in the trial of the woman's accused killer.

Sirochman, one of several witnesses to testify in Common Pleas Court on Wednesday about the crime scene where Sabina Rose O'Donnell, 20, was found on June 2, 2010, said that as soon as she called police from her nearby home, she returned to the lot.

"That was someone's child laying there, and I didn't want her laying there alone," Sirochman said tearfully.

Jurors in the trial of Donte Johnson, the 20-year-old man charged with O'Donnell's rape and murder, heard testimony Wednesday about O'Donnell's injuries. Prosecutors allege Johnson spotted O'Donnell as she was biking to her home at Fourth Street and Girard Avenue, dragged her about 100 feet to the lot behind the building where she lived, then beat, raped, and strangled her. He later told police he had wanted to steal her bike.

Assistant Medical Examiner Edwin Lieberman, who examined O'Donnell's body, testified that she was covered with bruises and cuts, including gashes on her head, bruises from blows to the face, and scrapes on her torso that prosecutors allege came from being dragged. The tip of her tongue was bitten through, Lieberman said, and her green bra was knotted around her neck in what Lieberman said was "one of the tightest ligatures I've seen in a long time."

O'Donnell also had internal bruising that prosecutors say was consistent with sexual assault. Authorities have said they found Johnson's DNA in and on O'Donnell's body.

Jurors were shown photographs of the crime scene as well as O'Donnell's white jeans shorts and flowing white short-sleeve blouse, which were displayed on a small mannequin, wrinkled and caked with large splotches of dried blood.

Johnson's attorney, Lee Mandell, questioned Sirochman about a man she spotted near the scene just before she found O'Donnell. Sirochman testified that she turned and saw the man standing on the far side of the lot, on North Orianna Street. When Sirochman took a step toward the man, he ran away, she said. She described him as black and in his late 30s or early 40s, possibly around six feet tall. The first police officer on the scene testified that she radioed a description of the man to patrol cars that morning, but it is unclear whether he was ever identified. Police have never identified any other suspects in the case.

Contact Allison Steele at 215-854-2641, asteele@phillynews.com, or follow on Twitter @AESteele.