Days after a threatening note was found in a Mexico City university, a young woman was shot dead as she sat in class.
Aidee Mendoza, 18, was a science and humanities student at the National Autonomous University of Mexico (UNAM). She died on Monday (local time) after being struck by a bullet as she studied in a classroom.
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No one knows who shot her, or even where the gunshot came from. Local media reports the 10 other students who were in the classroom at the time believe the shot came from outside the room.
Some said they heard a "soft" noise before they realised Mendoza had been shot, which investigators have taken as proof the culprit fired the gun from outside the classroom.
The bullet hit her under the armpit, causing fatal internal haemorrhaging.
Several days before the shooting, a note was found in the same room which read: "The day is coming, you guys cannot hide the truth."
The note also included the date of the attack, local media reports.
Mexican authorities are investigating both the note and the bullet in an attempt to find out who killed Mendoza and why.
Her death is currently being treated as a femicide or 'feminicidio' - the deliberate killing of a woman because of her gender - which is a disturbingly common crime in some parts of Mexico.
Women's rights activists have accused the Mexican government of covering up the country's high rates of missing and murdered women, or blaming drug cartels for gendered violence without investigating further.
In the wake of Mendoza's death, UNAM students gathered on campus to demand that her killer be brought to justice.