In the hills overlooking Granada, forensic archeologists buzz excitedly around a cordoned-off site. A blue tarp sits in the middle, marking the spot where they believe lies the answer to one of Spain’s great mysteries of recent times. Since mid-November, the team has been working from sunrise to sunset to locate the remains of playwright and poet Federico García Lorca.

It is on this barren patch of land, just up the road from the tiny village of Viznar, that the author of Blood Wedding and The House of Bernarda Alba is thought to have been shot by a rightwing firing squad in 1936.

The findings have so far been encouraging, says lead archaeologist Javier Navarro. The final resting place of one of Spain’s most famous civil war victims was flagged in a 2011 book detailing his final hours. “Everything we’ve done to date confirms that this is the spot we’ve been looking for,” said Navarro.

The search for Lorca’s remains made headlines around the world, but the attention masked an increasingly common complaint across the country. Seven years after the country passed legislation designed to make it easier for Spain to confront its past, campaigners say searches of the more than 2,000 known mass graves are becoming increasing difficult to carry out.

When Spain’s then-socialist government introduced a historical memory law in 2007, many heralded it as a crucial first step towards recognising the country’s murky past. The law removed Francoist monuments and symbols from public places and made it easier to locate and dig up the estimated 114,000 people who disappeared during the 1936-39 civil war and the ensuing dictatorship that ended only after Franco’s death in 1975.

But little has progressed in recent years, said Emilio Silva of the Association for the Recovery of Historical Memory. In 2000, he sparked a movement when he carried out the first scientific dig for the remains of his own grandfather and a dozen other victims from a mass grave in northern Spain. His group has since gone on to find some 6,000 bodies.

The historical memory law provided four years of subsidies, helping Silva’s group locate 5,400 bodies. But when the right wing People’s party came to power in 2011, funding stopped.

Technical staff start excavations in a park near Granada, where Federico Garcia Lorca is believed to be buried. Photograph: Jorge Guerrero/AFP/Getty Images

Few were surprised. As he campaigned to become prime minister in 2008, Mariano Rajoy voiced his concerns that the law exacerbated divisions in the country, telling Spanish media: “I would eliminate all the articles in the historical memory law that mention using public funds to recover the past. I wouldn’t give even a single euro of public funds for that.”

In the absence of secure funding, a patchwork system of different institutions and assistance has emerged among the country’s regions, with Catalonia, the Basque Country and Andalusia being the only ones to offer organised assistance to victims’ families. Silva’s group turned to fundraising – even crowdfunding in some cases – to pay for the digs. “The last exhumation was carried out thanks to a €6,000 [£4,750] donation from a Norwegian electricians’ union,” he said wryly. “It’s something that any government should be ashamed of, but it doesn’t seem to bother anyone here.”

The group has also attempted to secure funding from international organisations, with little success. “Many think that giving us money would be an insult to Europe, as it would imply that there is a problem with human rights. We’re in a limbo.”Volunteers carry out most of the workassociated with the digs, but the DNA testing is costly. The group’s go-to lab – which has always been lenient about payment – is on the brink of closure, he said.

Mount Estepar near Burgos, where the remains of people dumped in mass graves during the Spanish civil war were being unearthed this summer. Photograph: CESAR MANSO/AFP/Getty Images

Funding woes are compounded by a lack of political will to meaningfully address the past, said Silva. He pointed to Madrid’s Victory Arch, built to commemorate Franco’s victory in the Spanish civil war. “It’s located 800 metres from the residency of the prime minister. Every prime minister since the death of Franco has passed by the arch hundreds of times, but not one of them saw any contradiction between having a monument to a coup d’etat in a democratic culture.”His group gained a powerful ally in September when a United Nations working group on forced disappearances wrapped up an investigation in the country and concluded that the Spanish government must take political responsibility and draw up a plan to search for the country’s missing.

This search isn’t a task to be carried out by families, but an obligation of the Spanish state, said Ariel Dulitzky of the UN group. He called on Spain to overturn a 1977 amnesty law for crimes committed during the dictatorship and dismissed any worries about opening old wounds.

“The wounds are there,” he said. “They are open, and in the case of forced disappearances, they will remain open until we know what happened. They are not going to go away.” The Spanish government has until mid-December to respond to the UN group’s recommendations.

For many fighting for justice, time is running out. Ascensión Mendieta flew to Buenos Aires on her 88th birthday last year, where a judge has invoked the principle of universal justice to address Franco-era crimes. “I just want to take at least one of my father’s bones to my grave. Then I’ll die peacefully,” she told reporters last year, clutching a picture of her father as she embarked on the 6,000-mile journey. She was 13 in 1939 when her father, a local union leader, was shot after a summary hearing, Mendieta told the court. He had been turned in by a neighbour and a soldier for “aiding the rebellion”.

Her search for justice began in Spain but continued to run into roadblocks, said her daughter Chon Vargas. The case unfolding in Argentina soon seemed like the only real opportunity to investigate the past.

In February, the Argentinian court ordered Spain to excavate the patch of land in the Spanish province of Guadalajara where Mendieta believes the remains of her father lie and carry out a DNA test. The family is still waiting for the Spanish court to respond.

As her mother readies to Mendieta celebrated her 89th birthday on Saturday and Vargas was hoping to soon have an answer for her mother. “She’s in very delicate shape. But I’m hoping with all my heart that we’ll have good news.”High up in the hills of Granada, Javier Navarro took a break from the Lorca search to explain that if the playwright’s remains are found, a court will then determine the next steps. The archaeologist shakes his head as he contemplates finally being able to turn the page on a small part of a dark chapter in Spanish history. “They’re digging up graves in Bosnia and Herzegovina, and even Iraq, while in Spain they make things so difficult,” he said. “But in a civilised country you can’t leave people in a field as if they were scum.”