By Rupert Knox, Special to CNN

Editor’s note: Rupert Knox is a researcher on Mexico at Amnesty International. The views expressed are his own.

Less than a week ago, six Spanish tourists were allegedly raped in the holiday resort city of Acapulco in southern Mexico. The attack quickly made international headlines, and although local authorities initially appeared keen to downplay the story, spiraling public outrage and pressure from the Spanish authorities prompted a vow for a full investigation.

Sadly, those of us who follow events in this part the world were far from surprised by news of this truly dreadful crime – after all, thousands of women and girls in Mexico suffer sexual violence every year. Indeed, according to information Amnesty International presented to the U.N. Committee on the Elimination of Discrimination against Women in 2012, more than 14,000 women are victims of rape each year. The figure, based on data collected in 2009, also shows there were only 2,795 convictions that year. National studies, meanwhile, indicate that just a fifth of women report rape due to distrust in the justice system and fear, meaning the actual scale of sexual violence is likely to be far greater.

If asked about this issue, Mexican authorities would probably point to the several important steps they have taken to protect women from violence – including the passing, at federal and state level, of a law on “women’s access to a life free from violence.”

However, despite some positive advances, gender-based violence continues to be widespread, and federal and state authorities have systematically failed to ensure the effective implementation of many aspects of the new legislation, which has allowed impunity to persist.

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Inés Fernández Ortega and Valentina Rosendo Cantú, two indigenous women from the state of Guerrero know firsthand the injustices of the legal system.

They both claim they were raped by members of the armed forces in 2002. After years of stonewalling in which the case got lost in the military justice system, they won the right for their case to be moved to civilian jurisdiction, increasing their chances of a resolution despite the fact that even the civilian justice system frequently fails to hold perpetrators to account.

In the north of Mexico, meanwhile, hundreds of women have been murdered or simply disappeared since the early 1990s. With this in mind, last January, relatives of women murdered and disappeared in Ciudad Juarez, a town near the U.S. border, marched to demand the authorities properly investigate the crimes and bring those responsible to justice.

Women’s organizations in other states such as Nuevo Leon, Oaxaca and Mexico State have highlighted similar patterns of gender-based violence that the authorities have consistently failed to combat effectively.

Justice is crucial when it comes to tackling and ending violence against women. When those who rape women are not punished, a message is sent that such abuses are acceptable – effectively leaving the door open to others to commit similar crimes.

The high rates of general criminal violence affecting Mexico must not be used as an excuse to ignore or downplay what is happening to women across Mexico. Authorities at the federal and state level have simply failed to set up and implement measures to prevent and tackle these crimes.

It is time for the government to heed the demands of women’s rights organizations and others working in the field to move from talking about preventing violence against women and start acting. Concrete, effective measures are needed to improve investigations and to increase prosecutions and convictions.

The Mexican government owes women an unrelenting effort to stop the violence and support for the survivors of sexual abuse.