A Dutch court may decide on Wednesday if Shell was complicit in the Nigerian government’s execution of the Ogoni Nine, environmental activists who were trying to fight the petroleum company’s exploitation of their oil-rich homeland.

The widows of four of the activists accuse Shell of instigating a brutal crackdown against peaceful protesters that led to the deaths of the Ogoni Nine in 1995.

Two of the widows will be in court to hear the ruling, in their most recent attempt to get justice for their husbands, who were falsely accused of murder and hanged in secret under Sani Abacha’s military regime after what is widely acknowledged to have been a discredited trial.

“I want to see all the innocent ones exonerated,” said Esther Kiobel, whose husband, Barinem Kiobel, was among those executed.

Kiobel’s fight for justice is as much about her ravaged community as it is a personal one, she said in a telephone interview on her way to The Hague.

“Shell collaborated with my government, the late Abachan Nigerian government, to kill its people because of oil in Ogoniland,” she said. “As each day goes, our people keep dying in numbers, dying of cancer, dying of air pollution, the water – and they haven’t done anything concerning the pollution up till today.”

Shell denies all allegations that it was complicit in the deaths of the Ogoni Nine or human rights abuses, but it has acknowledged that it was aware that Nigeria’s military was taking action to protect the company’s infrastructure.

The protests in the 1990s were about the unfair distribution of oil wealth, the lack of development in Ogoniland, where Shell first started extracting oil in the 1950s, and especially oil pollution, which devastates the region to this day. A long-awaited cleanup of oil poisoning creeks and wells has yet to take place: the agency tasked with delivering it has spent more than two years and millions of dollars without laying a single brick of the centre for processing contaminated soil.

The family of Ken Saro-Wiwa, the Ogoni Nine’s most famous member and founder of the Movement for the Survival of the Ogoni People, is not part of the Dutch case. Saro-Wiwa’s family and several others brought a case against Shell in New York, but shortly before the trial in 2009 the company agreed an out-of-court settlement of $15.5m (£11.9m), without admitting liability.

Meanwhile, Esther Kiobel’s group, which had brought a separate class action against Shell in New York, carried on. After more than a decade, the US supreme court ruled that the case had been brought in the wrong jurisdiction, which is why it filed a writ in The Hague.

The court has not made it clear exactly what it will be ruling on. It may rule that Shell has lost or won, or it may decide that the company has to hand over internal documents that Kiobel’s team argues provide key evidence of its complicity, but which Shell has so far refused to disclose.

Shell had to give these documents to Kiobel’s American lawyers, but the Netherlands has stricter rules on releasing documents that may contain commercial secrets or personal information, so this evidence has not formed part of the case so far.

“We think it really does show that Shell did instigate the Nigerian military’s campaign against the Ogonis,” said Mark Dummett of Amnesty International. “They repeatedly asked for the intervention of the Nigerian security forces to protect their infrastructure or to intervene to stop Ogoni protests, which were disrupting their operations.”

The widows have been supported by Amnesty International, which is also urging the UK, Nigeria and the Netherlands to consider a criminal case against Shell over evidence it says shows the company is guilty of “complicity in murder, rape and torture” – allegations strongly denied by Shell.

Kiobel and Victoria Bera testified at the court in February, speaking about their attempts to get justice for their late husbands. Because they fled Nigeria and now live in the US and Canada respectively, they are able to attend tomorrow’s ruling, but the two other widows bringing the case, Blessing Eawo and Charity Levula, cannot as they were refused visas to travel from Nigeria.

For Kiobel, now 54, the events of 1995 have been “like a movie that never goes away”, the reel of how she imagines her husband’s hanging playing over and over in her head.

“He knew it was coming to pass and when he was killed – he was killed like an animal – he just cried out for his innocence,” she said, her voice quavering. “Heaven was angry. The weather was black. That day was so black.

“It was so painful and it’s so painful up till today. Each day of my life I go to bed with wet eyes. I will rest when justice is granted, to me and to my people.”