TUCSON, Ariz. – Briefly, they were 18-year-old freshmen sharing two things: their Navajo heritage and a University of Arizona residence hallitory room.

But less than three weeks after school started, something went terribly wrong between Mia Henderson and her roommate, Galareka Harrison.

On Wednesday, days after Henderson filed a police report accusing her roommate of stealing, a fight broke out between the two, and Henderson was stabbed to death, authorities said. Harrison was jailed on suspicion of murder.

“You wonder what could provoke them to be so aggressive toward another girl because you never think that girls are going to act so violently,” said Holly Polk, a student from Elkhorn, Wis., who lives in the residence hall where the fight occurred.

Both young women were from the sprawling Navajo reservation in Arizona and were living away from home for the first time. Both were enrolled in a special program designed to help American Indians adapt to college life.

Police would not say what Harrison had been accused of stealing and would not release the police report her roommate filed Aug. 28.

But Lee Ann Dejolie, a Northern Arizona University student who described herself as a close friend of Henderson’s, said Henderson had complained this week that her roommate had been going through her purse and taking things.

“So Mia was really ticked off,” Dejolie said.

A judge on Thursday set Harrison’s bail at $50,000. After the hearing, her mother, Janice, said her daughter has no history of violence. Noting the teen was injured and briefly hospitalized, she said her daughter must have been defending herself.

“She never did anything wrong,” the mother said. “She’s a real nice person. She’s never been away from home.”

Galareka Harrison had not discussed her roommate or spoken of any problems at school, Janice Harrison said.

Janice Harrison said her daughter wants to become a pharmacist, participated in high school track, and is heavily involved in rodeo and devoted to her three quarterhorses.

Henderson had attended a summer science program at the university, held a prestigious tribal scholarship and planned to major in biology.

About 200 people, including members of Henderson’s former softball team at Tuba City High School on the Navajo reservation, went to the school’s athletic field Wednesday night to remember her.

“It’s just tragic because the people in Tuba City know her really well, and Mia was a good kid,” said Hope MacDonald-Lonetree, a Navajo council delegate who represents Tuba City and grew up with the young woman’s mother. “She was known as a high-achiever; she was very congenial. She was not known to be in any kind of conflict or anything like that. She was just a good kid.”

When Henderson filed the police report, she told police that she would not stay in her residence hallitory room until either Harrison or she was moved, Police Chief Anthony Daykin said. Daykin said the roommate had also been named as a possible suspect in a theft report filed by another student in the residence hall.

The next day, Henderson declined an offer of different housing, Daykin said. The chief said Wednesday that he did not know when Henderson had returned to the residence hall room or what had triggered their fight.

But students called police shortly before 6 a.m. after hearing screams, and officers found both young women injured. Both were taken to a hospital, where Henderson was pronounced dead. Harrison was not seriously hurt.

Investigators would not say what kind of weapon was used.