A suspect in the slaying of a 21-year-old American psychology student living in the Dutch port of Rotterdam appeared before a judge Friday and was ordered detained for two more weeks while the investigation continues.The Rotterdam Public Prosecutor's Office tweeted that the 23-year-old suspect, whose identity hasn't been released, was brought before an investigating judge. The hearing wasn't open to the public.Sarah Papenheim, a native of Minnesota, was fatally stabbed Wednesday at her home in an apartment building near Erasmus University, where she had been studying since 2016.Rotterdam police said she died Wednesday after a stabbing in her home near the university. Police tried unsuccessfully to revive her after arriving at her home following reports of an argument.The suspect was arrested the same day at the railway station in the southern Dutch city of Eindhoven.The university said it was shocked by her death and was taking care of students and staff. Tributes, including flowers and candles, were left inside her apartment building."Our deepest condolences go out to all Sarah's family and friends at this poignant time," the university said.Fikret Egemen, the owner of a kebab restaurant where Papenheim worked part time, fought back tears as he recalled how she immediately fit into his team when she started working for him in September."From day one, she picked up everything. She was like family," he said. "She always worked with a smile, all day long, no problem. Angel."The university's school of social and behavioral sciences, where Papenheim studied, organized a meeting for friends and teachers."We encourage our students and staff not to let each other be alone in this difficult time and to get in touch with student advisers and psychologists if they want to," the university said.Papenheim's mother, Donee Odegard, told the Star Tribune newspaper in Minneapolis that her daughter was studying psychology with a focus on suicide. She said Sarah's brother took his own life three years ago."My only two kids, and I've lost them both," Odegard told the newspaper.She said her daughter, who played the drums, was due back in the United States and had a gig booked with a local musician on December 22. The newspaper said she was from Andover, Minnesota.Odegard told the Star Tribune the suspect was her daughter's apartment roommate and that he reportedly had been "getting more and more angry" in recent weeks. The suspect also was a musician, Odegard said."They'd talk music all night," she said. "They kinda clicked on that. Then as time went on, he'd get highs and lows."Amid concerns about the suspect's mental health, Odegard said to her daughter: "`Get out of there,' but she wouldn't listen to me," she told the Star Tribune.The newspaper reported that musicians are planning a concert to help fund the repatriation of her body. A Gofundme page for donations has raised over $22,000.