Friends of a 21-year-old woman whose naked body was found in a vacant lot yesterday, gathered last night near the crime scene to remember a woman described as a "total sweetheart."

"This is not supposed to happen," cried out one of the more than 50 friends at a candlelight vigil for Sabina Rose O'Donnell. "She was always sweet to everyone. She never did anything wrong."

O'Donnell was found in the lot on Girard Avenue near Orianna Street shortly before 10 a.m., according to Homicide Captain James Clark.

O'Donnell was apparently beaten and strangled, investigators said. Her body was found by a neighbor walking a dog.

Clark said investigators are awaiting test results to determine if O'Donnell was sexually assaulted.

O'Donnell, a waitress at P.Y.T, a bar and restaurant in the Piazza at Schmidts, was out with friends at El Camino Real, a bar and restaurant on 2nd Street near Germantown Avenue, and then went back to a friend's house near Front and Girard, Clark said.

Around midnight, O'Donnell asked to borrow a friend's bike to ride home to the house she shared with her stepfather on 4th Street near Thompson.

"When she got to the outside of that location, she was approached by an unknown male who dragged her to the rear of that property, took all of her clothes off of her, savagely beat her about the head and body and, we believe, strangled her and robbed her," Clark said.

Investigators found the contents of O'Donnell's purse but not the purse itself, Clark said.

Yesterday as police gathered evidence, friends who heard the news were stunned.

"I almost fell out of my chair, I couldn't even talk," said Dennis Wolffang, O'Donnell's friend and a local DJ. "She's a total sweetheart, every time I saw her she was happy."

Wolffang said that O'Donnell, an aspiring model who has worked with Fresh Melt Water and the Topstitch Boutique, both clothing companies in Northern Liberties, loved music and dancing.

She had moved recently to Philadelphia from California.

"She would come to all my parties," Wolffang said.

Wolffang hopes that whoever is responsible for the vicious murder of his friend comes forward.

"This was a beautiful young girl who never hurt anybody," he said.

"Come forward so this family can start their grieving."

Staff writer Regina Medina contributed to this report.