CAMBRIDGE, Mass. -- For years, Harvard Square has been a place for young people to get together with friends, to fit in when they might elsewhere be considered misfits, to sleep when they might not have a home.
Io Nachtwey, a 22-year-old college dropout from Hawaii, was drawn to this spot, a sunken plaza known as "the pit," next to the subway stop and across from the red brick buildings of the nation's oldest university.
It was there that she made friends.
It was also where she met her killers, police say.
Nachtwey's body was found in the nearby Charles River on Nov. 4. Prosecutors say she had been stabbed to death for refusing to join a gang. Six people -- four men and two women -- have been arrested.
"She was one of the most innocent people here," said Josh Mason, 17. "It's so cruel that she was the one who got murdered. She was a real sweetheart."
The attraction of Harvard Square is both practical and philosophical. Cambridge is accepting of those who often do not fit in elsewhere. It is also a major hub of public transportation. The subway and several bus lines bring tens of thousands of passengers to the square every day.
Nachtwey landed here this summer after dropping out of Maui Community College and traveling to the East Coast to stay with grandparents in Maine, friends said. The plain-looking young woman managed to make friends amid the multicolored hair, the tattoos and the body piercings.
She would panhandle outside shops, always with a smile. At night, when many of the other kids went home, Nachtwey would curl up to sleep with other homeless in a cemetery.
Nachtwey, who a few years ago had been named the best female dancer in her senior year at Kekaulike High School, often gave an impromptu dance in the square.
Authorities say some of those charged in Nachtwey's death had tried to recruit more than a dozen youths from the pit as gang members. For initiation, recruits would have to steal and then hand over the loot, prosecutors say.
When Nachtwey and others backed out, she was killed to send the others a message, prosecutors say. Her killers took her to the railroad tracks, stabbed her 15 times with knives, beat her with martial arts weapons and rolled her body into the river, police said.
Four men were jailed without bail on murder charges. Two 18-year-old women -- one of them from the upscale suburb of Milton, the other a former Boston-area high school cheerleader -- were charged with being accessories for allegedly pushing Nachtwey onto the tracks while the others stabbed her.
Bill Sugane, a foreign-language teacher at Nachtwey's high school, remembered her as an average student, outgoing and self-assured.