Rachel Rose last saw her best friend, Diamond Williams, on Old York Road in the city's Hunting Park section earlier this month.

Williams was caught up in the world of drugs and prostitution, but she didn't let it get her down, said Rose, 30.

For transgender women facing discrimination in mainstream society, resorting to the sex trade "is a matter of survival," said Aamina Morrison, 33, of the Trans-Health Information Project.

The risky occupation turned fatal when, according to police, Williams was picked up by Charles Sargent, who took her to his home in Strawberry Mansion sometime around July 13.

Police say Sargent, 43, killed Williams and dismembered her body, scattering her remains in a weed-choked field near York Street and Sedgley Avenue.

About 150 people gathered Tuesday evening at John F. Kennedy Plaza to remember Williams, 31, of Ogontz, and decry violence against transgender women.

Some held signs that read "Our Lives Are Not Expendable," "Transphobia Kills," and "Justice for Diamond."

Police said Sargent confessed to the slaying, saying he became enraged when he discovered Williams was transgender. Williams was also known as Mark Williams.

Gloria Casarez, Mayor Nutter's liaison to the lesbian, gay, bisexual, and transgender communities, urged the LOVE Park gathering to fight any "she-tricked-me defense" the alleged killer might use.

Casarez cited the unsolved slayings of transgender women, including Kyra Kruz, who was shot to death in September.

Williams "made some choices in life that were unsavory for some people, but we loved her," Morrison said.

Friends spoke warmly of Williams, who had a diamond tattoo near her wrist, for her personality and interests.

"She was very much into music and poetry," said Christian Lovehall, 28.

Lovehall said the last time he saw Williams, she complimented him on his nose ring and asked why he got it.

He mentioned Tupac Shakur, who also had a nose ring, "and in that moment her face lit up," Lovehall said. What followed was a 30-minute conversation on hip-hop and poetry.

"She had a warm and loving spirit," Morrison said.

Contact Robert Moran at 215-854-5983 or bmoran@phillynews.com, or follow @RobertMoran215 on Twitter.