The Dutch football association has deducted 18 points from Vitesse Arnhem, officially confirming the club’s relegation, in the wake of an investigation by the Guardian and the Bureau of Investigative Journalism (TBIJ) that uncovered apparent financial ties between the club and the Russian oligarch and former Chelsea owner Roman Abramovich.

The KNVB, the governing body of Dutch football, said it had imposed the record sanction because the club, formally known as SBV Vitesse, failed to meet the requirements of its licensing regulations.

Related: Roman Abramovich secretly bankrolled Dutch football club, leaked documents suggest

The sanction will reduce Vitesse’s points tally to -1, sealing demotion to the second division from the Eredivisie, where the club have played for 35 years. The club, who are in the midst of a financial crisis, were already bottom of the Eredivisie with four games to go.

The KNVB said the unprecedented scale of the penalty was due to the “exceptional seriousness and extent” of violations by Vitesse of the Dutch football licensing system.

It said Vitesse had provided “incorrect information” that was important for a forensic investigation of whether it had breached sanctions law. It said Vitesse had also withheld vital information.

The Dutch ministry of economic affairs and climate change is still investigating any ties to Abramovich, in the light of EU sanctions imposed against the Russian oligarch in 2022, part of an international effort to target wealthy and powerful Kremlin allies in response to the invasion of Ukraine.

The KNVB’s licensing committee said it had concluded that there were “indications” that Abramovich had controlled, or still controlled, Vitesse and that there were “risks” that sanctions had been violated. It said it would await the outcome of the ministry’s investigation.

In a statement on their website, Vitesse said the deduction had been “inevitable”, citing factors including their submission of incorrect half-yearly financial figures and their inability to demonstrate that they did not have ties to Abramovich.

“Although this is a dark day for everything and everyone who cares about Vitesse, this is the harsh reality,” said Edwin Reijntjes, CEO of the club.

The club can appeal against the decision but said they would not do so and would focus on retaining their football licence. The KNVB’s licensing committee will also consider further sanctions, depending on whether the club provide any further information, including plans for a financial restructuring.

It comes after the Guardian and TBIJ uncovered documents, derived from a leak known as the Oligarch Files, that appear to show that Abramovich secretly poured more than €100m into Vitesse.

While Chelsea and Vitesse were known to have a close relationship, with the London club frequently sending players on loan to its Dutch partner, the two teams had previously denied that the oligarch was involved in funding Vitesse.

The revelations prompted a third investigation by the KNVB into the funding of Vitesse and any ties to Abramovich, after inquiries in 2010 and 2014-15.

Abramovich, who has had sanctions imposed by the UK and the EU over Russia’s invasion of Ukraine, has previously declined to comment on the matter. The Guardian has approached representatives of Abramovich for further comment.

The Premier League is still investigating allegations, also revealed by the Guardian and TBIJ, that companies owned by Abramovich used offshore vehicles to pay expenses that should have been borne by Chelsea FC. Chelsea have previously said that the allegations pre-date the tenure of the current owners, a consortium led by Todd Boehly that bought the club after Abramovich’s assets were frozen.