There's a chill in the air in the Mexican city of Puebla, and a dozen people have gathered in front of the local prosecutor's office to lay out candles and photos of a teen with a braces-filled grin printed with the words "Justice for Paulina."

"My sister was my best friend, I could always pick up the phone and talk to her about anything in my life," Rolando Camargo says of Paulina. "That all changed overnight. It is very frustrating. Who can I talk to now?"

Paulina Camargo was four months pregnant when she went missing on August 25 last year.

The 19-year-old was one of six pregnant women murdered or disappeared in the last two years in the state of Puebla, that borders Mexico City. Their cases have channelled latent outrage at the wider issue of a sharp increase in the number of femicides — women killed in part because they are women — that have turned the state into the latest hotspot in a national crisis.

A local NGO called the Citizen's Observatory on Reproductive and Sexual Rights, known as Odesyr, has documented 178 cases of femicide in Puebla since 2013. The group says that these are occurring three times more often today than they did at the turn of the decade.

"It's just one after another after another, after another," says Camargo. "Hardly any time goes by before it happens again. This is almost a massacre."

Paulina's family is sure that she was abducted and murdered by José María Sosa, the father of her child. They say that Sosa initially ran from the idea of parental responsibility when he heard Paulina was pregnant, but later got back in touch and said he wanted to be involved. The family says they met with him on the day Paulina disappeared, and then left the couple alone to chat in a cafe.

They never heard from her again.

Sosa accompanied the family to report Paulina's disappearance claiming that he had sent her off in a taxi. Two days later he turned himself in, confessing to having strangled the teenager and dumped her cadaver in a nearby garbage bin.

Since his detention a Facebook page has emerged in his defense claiming that he was tortured into confessing. Local media outlets reported that the government has combed through five tons of garbage looking for Paulina's corpse but her remains have still not surfaced. Sosa is facing charges of homicide and aiding an abortion, which is illegal in the state.

But Paulina's family so distrust the judicial authorities that they feel they have little hope of justice being done unless they keep up the pressure with the vigil they hold every Friday night. They also want more efforts made to find her body.

'This is a macabre message because it shows that people... don't care much about the lives of other women who weren't pregnant.'

Social media has also been key to their campaign. Photos of a visibly pregnant Paulina have gone viral and prompted shows of support that are rarely seen in femicide cases.

"The society in Puebla identifies more with this type of women. People think it could be my daughter, my niece, or my friend," said Vianeth Rojas, director of the reproductive rights organization Odesyr. "This is a macabre message because it shows that people, especially media outlets, don't care much about the deaths of other women if they weren't pregnant."

Rojas adds that Paulina's case has also received relatively more sympathy because her family is financially better off than those of many other victims, and so able to dedicate more money and resources to the case.

The Puebla authorities refused requests for an interview about Paulina's case, or that of another pregnant young woman called Samaí Márquez, whose murder on February 24 sparked demonstrations against the increase in violence towards women.

Samaí's former boyfriend, Rafael Portillo, has also now been detained, after he reportedly confessed to killing her with a bullet to the head, and later dumping her body in an open field.

Local media reported that a text message exchange exists in which he offered 280 dollars for someone to kill her. Portillo, who is married, was having an affair with Samaí when she became pregnant.

Friends and family have created the Facebook page Justice for Samaí where they share information on other women who have been disappeared, and provide safety tips.

The doubts expressed by many in Puebla that justice will be done, even in cases where there are suspects facing trial, draw from the cases in which the men accused have faced no lasting consequences, even when the evidence against them appears strong.

The skepticism is also fueled by a long history of impunity for crimes against women across the country.

Femicides in Mexico first grabbed attention in the mid-1990's in the northern border city of Ciudad Juárez, when the bodies of young factory workers began turning up in the desert on the city's outskirts. The phenomenon drew the international spotlight and even prompted Hollywood movies, but this did little to help.

"What happened in Juárez was total impunity and total corruption along with the availability of very cheap labor," said Lourdes Pérez, the director of an academic research body called the Observatory on Social and Gender Violence in the City of Puebla. "The [government] didn´t address the problem, there was no public policy implemented nor special programs, and now this problem has spread all across Mexico like a cancer."

So far, activists say, progress in tackling the phenomenon of femicide has been largely limited to legislative changes sparked by a 2009 decision handed down by the Inter-American Court on Human Rights on the so-called "Cotton Field Case." The case referred to three young women found dumped in a cotton field in Juárez in 2001. The ruling said the authorities were complicit in the horror because of their blatant failure to investigate the crimes.

That 2009 ruling triggered legislative reforms in many Mexican states, including Puebla, to include the crime of femicide in their penal codes.

Puebla's law defines the murder of a woman as femicide if it meets certain criteria. These include pregnancy, the victim being abducted before being murdered, or their body being dumped in public. The law also considers that a history of violence or jealousy in an intimate relationship, violence in a workplace, or cruel treatment of the cadaver, are further indications of a femicide.

But, however apparently progressive the law, activists say the local authorities today are pretending that the problem does not exist. They point to comments made last month by Puebla's attorney general Victor Carrancá who said the media "has sought to portray" the state as being in the midst of a femicide crisis. This, he insisted, "is not the truth."

The protests around the cases of Paulina, Samaí, and the other assassinated women, have included calls for the state government to declare a "Gender Alert," though this looks unlikely. It would require the authorities to dedicate more resources to combatting gender-based violence, developing special programs to confront the problem, as well as intensify investigations into existing cases.

Even if it is declared there is no guarantee that it will make much of a difference. A similar alert was issued last summer in neighboring State of Mexico, which has the highest rate of femicide in the country. This week activists and relatives of victims held demonstrations in the state to denounce that the alert has not been accompanied by action that that femicides continue unabated.

Watch the VICE News Documentary: The Femicide Crisis in the State of Mexico

The situation in both the State of Mexico and Puebla fit within the context of a doubling in the number of women murdered across Mexico over the past decade with an average of seven killed every day between 2011 and 2013, according to official figures. Activists say that the evidence that a growing number of these murders were motivated by the victims' gender means the phenomenon should not be hidden within the wider rise of total violent deaths.

The murder of pregnant women has, so far, only been explicitly noted in Puebla and its origin is far from clear.

'These men prefer to become murderers who commit femicide than responsible fathers.'

Natali Hernández, a local reproductive rights advocate, believes it has something to do with the state's particularly conservative reputation and draconian laws, such as a near total prohibition on abortion. She believes that when women do not have the option to terminate an unplanned pregnancy it often puts a further strain on a relationship that may have already been violent.

"These men prefer to become murderers who commit femicide than responsible fathers, and maybe this has to do with a judicial system that is dominated by impunity," Hernández says.

The activist points out that while there are suspects in jail for the high-profile cases of Paulina and Samaí, most murderers rarely see a courthouse.

"You assassinate a woman and nothing happens to you," she adds. "No one will judge you."