The hashtag #JusticeForUwa is trending in Nigeria, with her family appealing for help to track down her killers.
Uwavera had been studying in a "quiet" church near her home in Benin City when she was killed, her sister, Judith, told BBC Pidgin.
The student, who had wanted to become a nurse, died in hospital on Saturday, three days after the attack.
Judith Omozuwa said her sister had also been raped.
Her family said they received a call from a woman at the Redeemed Christian Church of God on Wednesday evening.
Uwavera was taken to hospital after a security guard found her, her skirt torn and her shirt covered in blood, Judith Omozuwa said.
However, a police spokesperson in southern Edo State, whose capital is Benin City, told BBC Pidgin that they were treating the incident as a murder, not a rape, case.
The student died following a fight at the church, the spokesperson added, without giving more details.