It may be the Netherlands’ most religiously devoted community, where television and dancing are spurned by some as the devil’s work. But the wrath of God for indulging in those pursuits is unlikely to be the most pressing concern at the moment for some of the 20,000 residents of Urk, for centuries a major centre for Dutch fishing.

During an ongoing trial of five people, including three of the town’s fishermen, suspected of attempting to smuggle 261 kilos of cocaine worth €6.5m in their cutter boat, claims have emerged that the town’s fishing community has been infiltrated by a gang using financial favour and threats of violence, and even murder, to keep their hold.

Those on the boat, Z181, are accused of taking the stash of cocaine onboard from a container ship on the orders of a Dutchman of Pakistani descent who was working with a Montenegrin henchman.

With cocaine production in South America said to be at an all-time high, it is claimed the tight-knit community is the latest to fall foul of an urgent need among smugglers for fresh ways into mainland Europe.

The breaking up of drug cartels in South America has opened up opportunities for European gangs, according to Dr Axel Klein, an expert in drug smuggling. In 2016 an estimated 866 tonnes of cocaine were produced at clandestine labs in Colombia alone, according to the UN Office on Drugs and Crime (UNODC). In 2015, the estimate was 649 tonnes.

Urk’s harbour Photograph: Judith Jockel/the Guardian

Urk’s close community, reluctant to seek help from outsiders, may have been an enticement to the drugs gang. The local council admitted of the fishermen: “They don’t talk.”

In an opening hearing of the case against the men, the public prosecutor in charge of the case, Koos Plooij, made it plain that he suspected that a tight grip has been kept on the Urk fishermen through a variety of means, including in one case the threat of a grenade being thrown into a front room. “Urk has a ... problem,” Plooij told the court. “The mixing of legal fishing with international drug trafficking is worrying, especially in the light of the revealing reports about pressure and threat.”

On Urk’s docks, a man wearing a luminous jacket with “harbour master” written across the back, was loathe to speak to the Guardian, as he unloaded fish into a van. He said: “No comment, it was one boat. No comment.” The mayor of Urk, Pieter Van Maaren, an elder of the Dutch Protestant church, was apparently “very busy” in his office when asked for an explanation at the town hall.

The mayor’s spokeswoman, Marianne Heida, instead took questions, insisting the scandal had “come out of the blue” to the town, which was an island until 1939, and retains its own anthem and strong dialect to this day. More than one Urk boat may have been lured into the criminal gang’s web, she had picked up from from the trial, but the council had no idea what would happen next, Heida admitted.

Marianne Heida, spokeswoman for the village of Urk Photograph: Judith Jockel/the Guardian

“In 2008 the economy went down and the fisheries [all over the country] were very bad,” she said. “They say, but it is a rumour, ‘The fisheries are bad, the loans are bad, the criminals were coming up and going to the fishermen, saying here do something of us’,” she said. “We didn’t know that. Only when they were picked up in June. And then it was ‘Oh, maybe there is a relation between the economy in 2008 and this point’.”

“It was out of the blue for us,” Heida added. “We didn’t know there was criminal activity here. They don’t talk, the community, if they have a problem they will solve it themselves.

“That’s sometimes difficult. Also I think that is a problem of the Dutch people. You are proud. You want to manage yourselves ... They didn’t go to the police and say we were threatened, can you give us protection. We heard it also during the trial.”

Heida added of Urk: “When you were born here, you will stay here. You don’t go out of Urk. That’s the main thing. Everyone knows each other.”

Monument to Urk fishermen, with wind turbines in the background Photograph: Judith Jockel/the Guardian

The boat at the centre of the current court case – which is due to resume in February – was bought and renovated by Johannes Nentjes, 31, and his father in 2015, to fish Norwegian lobster and plaice.

Johannes’s mother, Hennie, took three goes to break a bottle of champagne against the bow of the ship when it was christened, according to the local press. A party was held at the Het Achterhuis restaurant overlooking the harbour. Approached by the Guardian about threats of violence to fishermen, there were nods of those at the bar. “But it isn’t for me to say,” said one.

Pim Visser, director of the VisNed, the representative group for cutter boat fishermen, insisted that it was a matter of “a few rotten apples”. He added: “And we have a big basket of apples.”