The revelation by Rodolfo Reyes, a Neruda nephew, is the latest turn in one of the great debates of post-coup Chile. The long-stated official position has been that Neruda died of complications from prostate cancer, but the poet’s driver argued for decades that he was poisoned.

There was no confirmation of Reyes’ comments from forensic experts from Canada, Denmark and Chile who are scheduled to publicly release a report Wednesday on the cause of Neruda’s death.

The public release of the group’s finding has been delayed twice this year, first due to internet connectivity issues of one of the experts and then again because a judge said the panel had yet to reach a consensus.

International forensics experts several years ago rejected the official cause of death as cachexia, or weakness and wasting of the body due to chronic illness — in this case cancer. But at that time they said they had not determined what did kill Neruda.

In an interview with The Associated Press, Reyes said forensic tests carried out in Danish and Canadian labs indicated a presence of “a great quantity of Cloristridium botulinum, which is incompatible with human life.” The powerful toxin can cause paralysis in the nervous system and death.

Reyes first revealed the information to the Spanish news agency EFE earlier Monday.

As a lawyer in the judicial case over his uncle’s death, Reyes said he has access to the forensic report, which was carried out after the same group of experts said in 2017 that there were indications of a toxin in the late poet’s bones and a molar.

The lab tests concluded that the toxin was administered when the poet was alive, Reyes said.

The report is set to be released almost 50 years after the death of the poet and Communist Party member and 12 years after the start of a judicial investigation into whether he was poisoned, as his driver Manuel Araya maintains.

Araya told AP earlier this month he was confident that the forensic findings would support his assertion the poet died after being given “an injection in the stomach” at the clinic where he was hospitalized. Araya said he first heard that version of events from a nurse.

Neruda, who was 69 and suffering from prostate cancer, died in the chaos that followed Chile’s Sept. 11, 1973, coup that overthrew President Salvador Allende and put Gen. Augusto Pinochet in power.

Neruda’s body was exhumed in 2013 to determine the cause of his death but those tests showed no toxic agents or poisons in his bone. His family and driver demanded further investigation.

In 2015, Chile’s government said it was “highly probable that a third party” was responsible for Neruda’s death. Neruda was reburied in his favorite home overlooking the Pacific Coast last year.

In 2017, a team of international scientists determined that Neruda did not die of cancer or malnutrition, rejecting the official cause of death but not saying what he did die of.

“The fundamental conclusions are the invalidity of the death certificate when it comes to cachexia as a cause of death,” Aurelio Luna, one of the panel’s experts, said at that time. “We still can’t exclude nor affirm the natural or violent cause of Pablo Neruda’s death.”

Neruda, who was best known for his love poems, was a friend of Allende, who killed himself rather than surrender to troops during the coup led by Pinochet.

Neruda was traumatized by the military takeover and the persecution and killing of his friends. He planned to go into exile, where he would have been an influential voice against the dictatorship.

But a day before his planned departure, he was taken by ambulance to a clinic in Chile’s capital of Santiago where he had been treated for cancer and other ailments. Neruda officially died there Sept. 23, 1973, from natural causes.

But suspicions that the dictatorship had a hand in the death remained long after Chile returned to democracy in 1990.

The former Mexican ambassador to Chile at the time of the bloody military coup, Gonzalo Martínez Corbalá, told AP on two occasions that he saw Neruda the day before his death and that his body weight was close to 100 kilos (220 pounds). Martínez spoke to AP by phone in 2017, a few days before his death.

Araya told AP last month he still thinks that if Neruda “hadn’t been left alone in the clinic, they wouldn’t have killed him.”

He recalled that on Neruda’s instructions, on Sunday, Sept. 23, the poet’s wife, Matilde Urrutia, and he were at the mansion to pick up the suitcases that would be taken to Mexico the following day. In the middle of the afternoon Neruda asked them to come back quickly. He died that same night.

During his life, Neruda accumulated dozens of prizes, including the 1971 Nobel Prize for Literature, but in recent years criticism has appeared from feminist groups over a rape he committed in the 1930s and which he recounted in his book “I Confess That I Have Lived.” He also is criticized for abandoning his only daughter, Malva Marina, because she was born with hydrocephalus.