Buenos Aires, Argentina - On October 8, in the Argentinian seaside city of Mar del Plata, 16-year-old Lucia Perez left school for the last time.

She went to buy marijuana from someone she had never met, investigators hypothesise. When she arrived, she was force-fed drugs, gang-raped and penetrated by a wooden stick. Her alleged abusers then washed her body and left her at a hospital where she died.

The gruesome details of the crime sparked outrage in Argentina, where every 30 hours a woman is murdered.

Within two weeks, social activist group Ni Una Menos (Not One Woman Less) had mobilised to denounce this brutal crime. On October 19, thousands of protesters shut down the streets of Buenos Aires in memory of Perez, holding signs reading: "We want women alive" and "Machismo kills".

The brutal murder of Perez soon became a national and international symbol of the horrific violence women face around the world. In Latin America, a movement against gender violence is growing with Argentina at the forefront.

Ni Una Menos, a collective of artists, activists and journalists, first took to the streets of Buenos Aires in June 2015 in response to a string of femicides, defined by the UN as the violent, deliberate killing of a woman.

"When we women decide to take control of our own lives, we confront an increase in cruelty, which is what we see with these deaths," said Mariana Carbajal, a founding member of Ni Una Menos and journalist who covers gender violence in Argentina.

"They don't stop with killing [the woman]. They have to torture, destroy and obliterate their bodies."

In Argentina, at least 1,800 women have been murdered since 2008, according to La Casa del Encuentro, a women's rights organisation in Buenos Aires, yet only some cases rise to the fore of public consciousness.

Cases such as that of Perez are some of the most brutal, but they only tell part of the story of gender-based violence in Argentina.

It's often women with the least resources who suffer the most, according to Carbajal, although gender violence affects women of all classes, races and ages in Argentina.

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Femicide in the slums

In the slums of Buenos Aires, home to an estimated 275,000 residents, a smaller, grassroots movement against femicide is also brewing, focusing on the unique challenges poor, marginalised women face.

Just weeks after Perez's murder, another lesser-known femicide sparked outrage in Villa 21, one of the city's poorest neighbourhoods, about five kilometres south of where camera crews set up to capture the national outcry over Perez's murder.

On October 29, Elida del Valle Barrios, a 39-year-old Paraguayan immigrant and resident of Villa 21, was stabbed more than 20 times by her husband in a public plaza. She bled to death in front of her seven-year-old daughter while neighbours said the ambulance took more than an hour to arrive. The mother of two had recently filed a domestic violence report and was trying to leave her husband, according to neighbours and friends.

Appalled by the murder, community members organised a local march to honour her life the following Saturday, with only community media covering the event. A few hundred protesters gathered in the plaza where del Valle Barrios was killed, a modest number compared with the thousands who filled Buenos Aires' city centre after Perez's death.

"The protest was a sensation that came about organically to say this can't happen without consequences," said Maria Eugenia Noguiera, who works in Villa 21 with La Campora, an organisation that fights for social justice and economic equality.

"The community has to organise and go out [to the streets] feeling empowered and knowing that they can make demands," Noguiera said.

Nearly half of all homicides in Buenos Aires occur in villas, informal settlements which house about 10 percent of the city's population. In 2015, about one in three female murder victims was killed in a villa, even though these neighbourhoods are home to a small fraction of the city's residents. An estimated 80 percent of femicides are committed by someone who knew the woman, most often her current or former partner.

One of the most recent cases was on the morning of December 29, when a 22-year-old woman was shot in the head in Villa 21. Police are still searching for her boyfriend, the prime suspect in the case, who a neighbour said they saw fleeing the house shortly after a shot was fired.

Without adequate economic resources and social support systems, women such as del Valle Barrios are more vulnerable to gender-based violence and find it harder to escape these situations.

"Femicide and gender violence can't be combated in a vulnerable neighbourhood in the same way as in another area [of a higher socioeconomic class]," said Lorenzo de Vedia, a priest in Villa 21 known as Father Toto.

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Elida del Valle Barrios' story

Del Valle Barrios moved to Villa 21 from Paraguay with her husband and two children less than a year ago.

She had no other family in Buenos Aires besides an estranged brother who lives in another part of the city, according to community members who knew her. She quickly became part of the local community, selling Paraguayan food to make a small sum of money on her own. Her children were enrolled in the local school and always behaved well, according the the school principal.

But there were signs that her husband, who worked in construction, was a heavy drinker and often became violent, according to Father Toto. Friends close to her said she was trying to leave him, but that she had no way to provide for her children financially.

"She had filed a report. The problem was her economic situation," said Noguiera of La Campa. "He took care of her financially. They arrived recently from Paraguay and she was never able to get on her feet financially."

While trying to leave her husband, del Valle Barrios faced many of the problems that affect women in marginalised areas of Argentina.

Many women rely on their husbands to provide for them and their children.

As immigrants from the nearby countries of Paraguay, Bolivia and Peru, women in the villas often have fewer social networks to support them. Filing a domestic violence report doesn't guarantee protection, according to Noguiera. Women are often sent back to live in the same neighbourhood as their abuser and police can take hours to respond to calls.

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Absence of authorities

The case of del Valle Barrios also illustrates the failure of the government to help vulnerable women, according to Noguiera. She said that the state is absent in these communities, a sentiment echoed by other residents and community leaders.

"You have [these services] in theory, but they don't complete the function they are supposed to," said Marisa Guidolin, principal at the school where del Valle Barrios' children study.

NGOs and the church fill in the gaps where they can, acting as mediators, support systems and refuges for many women.

But the government has to start playing its part, according to Father Toto. This means a timely police response, shelters for domestic violence victims and resources for women to gain economic independence, he said.

Over the past decade, residents have slowly begun to demand these services, but the government hasn't yet caught up to this social awakening, Father Toto added.

It can't just be the community trying to improve the situation, Noguiera said. "The state needs to be present too."

Carla Majdalani, director of communications for Consejo Nacional de las Mujeres (CNM), a government entity that oversees and coordinates various initiatives to prevent gender-based violence, told Al Jazeera that public policy aimed at preventing gender violence considers the experiences of all Argentine women, with special programmes targeted at villas and other vulnerable populations.

"The people who live in villas are the ones who understand the reality there," she said ."If it is understood [in the villas] that public services aren't reaching them, it's because something has to be happening in terms of accessibility."

Majdalani admits that there could be a breakdown in terms of delivering these services that has led to these critiques.

While residents wait for the government to act, Villa 21 won't forget del Valle Barrios.

The plaza where she was killed, unnamed at the time of her death, is now called December 8 Plaza, in honour of the day of the Virgin Mary, who is believed to protect women. The plaza was inaugurated this past December 8 with another procession in honour of del Valle Barrios.

But, said Father Toto, "with three or four protests, this isn't going to be resolved. This needs to be accompanied by a cultural shift and with justice".

Follow Anna-Catherine Brigida on Twitter: @ AnnaCat_Brigida