The families of 78 victims who suffocated to death in Thai army trucks two decades ago joined survivors on Friday to voice anger that those responsible will never be brought to justice.
As well as the 20th anniversary of the "Tak Bai massacre", Friday is also the day the statute of limitations expires, which will lead to the murder charges against seven suspects being dropped.
The massacre has long stood as an emblem of state impunity in the kingdom's Muslim-majority southernmost provinces, where an insurgency has rumbled for years between government forces and separatists seeking greater autonomy for the culturally and religiously distinct region.
"There is no natural justice in our country," Khalijah Musa, whose brother Sari was killed at Tak Bai, told AFP, saying those responsible deserved the death penalty.
"It's not equal... we in the southernmost provinces are not part of the (Thai) family. Our voices are just not loud enough."
Around a hundred relatives, survivors and supporters gathered at the cemetery of a mosque in Narathiwat province on Friday morning to pray at a mass grave for the Tak Bai victims.
"It feels like it was only yesterday. I don't think I can get over it," Mariyoh Chewae, who lost her brother in the incident, said.
"I hope the Thai state treats everyone equally no matter which religion we practise."
Prime Minister Paetongtarn Shinawatra -- whose father Thaksin was premier at the time of the massacre -- apologised on Thursday on behalf of the government.
But she said it was not possible to extend the statute of limitations or prolong the case, despite appeals from campaigners.
The Civil Society Assembly for Peace, a group representing survivors, victims and their families, urged the government to set up an independent fact-finding committee and involve international experts.
"What happened in the Tak Bai tragedy... is a crime against humanity," the group said in a statement.
- 'Not worth it' -
Security forces opened fire on a crowd protesting outside a police station in the town of Tak Bai in Narathiwat province, close to the Malaysian border, killing seven people.
Subsequently, 78 people suffocated after they were arrested and stacked on top of each other in the back of Thai military trucks, face down and with their hands tied behind their backs.
Mariki Doloh, who survived the incident but had to have a leg amputated, said he was still deeply traumatised by his experience.
"I was just passing by and the police arrested me," he told AFP.
"I don't understand why they did this to us. I didn't think I would survive."
In August, a provincial court accepted a criminal case filed by victims' families against seven officials, a move Amnesty International called a "crucial first step towards justice".
But the officials -- including a former army commander elected to parliament for the Shinawatras' Pheu Thai party last year -- have avoided appearing in court, preventing the case from progressing.
On Monday, the court is expected to formally dismiss the charges, ending a case that has become synonymous with a lack of accountability in a region governed by emergency laws and flooded with army and police units.
No member of the Thai security forces has ever been jailed for extrajudicial killings or torture in the "deep south", despite years of allegations of abuses across the region.
The conflict has seen more than 7,000 people killed since January 2004.
UN rights experts said they were "extremely alarmed" that the Tak Bai case was closing with no one put on trial.
"Failure to investigate and bring perpetrators to justice is itself a violation of Thailand's human rights obligations," the UN experts said in a statement on Thursday.
In 2012, the government of then-prime minister Yingluck Shinawatra -- Thaksin's sister and Paetongtarn's aunt -- paid the families of each of the dead 7.5 million baht ($220,000) in compensation.
But Parida Tohle, 72, whose only son Saroj, 26 died in one of the trucks, said the money meant little.
"In exchange for my son's life it was not worth it," she told AFP.