Pablo Neruda, the poet who could write the saddest lines, has released a sombre verse from his grave.

International forensics experts concluded on Friday that the Nobel laureate did not die from prostate cancer, as his death certificate states.

They said that a new bacteria was found in Neruda's remains, and raised the possibility that a "third party" may have played a role in his death.

"What is 100 percent certain is that his death certificate does not reflect the reality of his death," Spanish forensics expert Aurelio Luna told reporters gathered in Santiago.

He said that it cannot be confirmed that Augusto Pinochet's regime injected Neruda with the bacteria golden staph, employed by Pinochet against dissidents.

"There is testimony and declarations, but there are no clinical documents that allow us to confirm or dismiss the existence of an injection," Luna said, adding that new studies of the bacteria are under way in Canadian and Norwegian laboratories.

Injection theory

The announcement caps a six-year inquiry into Neruda's death. In 2011, a Chilean court opened an investigation into the poet's final days after his former chauffeur and bodyguard, Manuel Araya, dropped a bombshell.

After 38 years of silence, Araya claimed that Neruda did not die from advanced prostate cancer in 1973 - just 12 days after General Augusto Pinochet seized power in a coup on September 11 - the official cause of death that is widely accepted in Chile. Neruda was murdered, Araya said.

On the day Neruda died, Araya told a Spanish newspaper, he was gathering the poet's personal belongings in preparation for his life in exile.

{articleGUID}

The following day, Neruda planned to fly to Mexico, where he would lead international opposition to the Pinochet regime. But when Araya returned to the Santa Maria clinic in Santiago two hours later, Neruda told him he had been injected with something. Neruda died that evening.

"This announcement marks a decisive, fundamental step toward the recovery of Chile's historical truth," Eduardo Contreras, Araya's lawyer, told Al Jazeera. "The discovery of this bacteria raises the strong possibility that Neruda's death was due to a third party."

Eerie similarities

In the years that followed the 1973 coup, Pinochet's secret police orchestrated several assassinations of high-profile opponents.

They include the killing of Carlos Prats, Allende's army commander, in a car bombing in Buenos Aires in 1974. And Pinochet, according to US intelligence documents, ordered the assassination of Orlando Letelier, Allende's former defence minister.

Letelier and Ronni Moffitt were killed by a car bomb in 1976 as they rounded Sheridan Circle in Washington, DC.

But the 1982 assassination of former President Eduardo Frei Montalva at the Santa Maria clinic provides eerie similarities to Neruda's death.

Frei, who had become a leading opponent of the Pinochet dictatorship, was murdered, a Chilean judge ruled in August. He charged six people, including three doctors, with involvement in the death.

"The same doctors, and the same nurse of the same clinic where Frei Montalva was assassinated in the 1980s, were the ones who examined Pablo Neruda in 1973, in a clinic occupied by the military," Contreras told Al Jazeera.

{articleGUID}

Araya's declaration has caused a stir in Chile, especially among Neruda's family. Rodolfo Reyes, Neruda's nephew and the family's legal representative until 2013, firmly defends the theory that the poet was assassinated.

Chile's Communist Party, which called for a formal investigation into Neruda's death, also embraces that view.

But critics - among them, Bernardo Reyes, Neruda's grandnephew - have poked holes in the assassination hypothesis.

They question why Araya waited 38 years to tell his story (Araya claims that for decades he tried to tell his story to anyone willing to listen).

Bernardo Reyes, a Neruda biographer, has called Araya a mythomaniac desperate for media attention.

In her memoir, Mi Life with Pablo Neruda, the poet's wife and muse Matilde Urrutia never mentioned Araya's claim.

But after the book's publication, in an interview with a Spanish newspaper, she expressed doubts about the involvement of a third party in her husband's death, pointing out that Neruda's prostate cancer was under control.