(ShareCast News) - The ongoing row between Petroceltic International and Worldview Capital Management has taken a new turn, after the latter has published an open letter alleging the company has committed "fraud and corruption".Worldview Capital, Petroceltic's largest shareholder with a 29% stake, had previously criticised the group over the management of its finances.On Thursday, however, Worldview stepped up its dispute by publishing an open letter to the London-listed company, in which it alleged the group's project director Geoff Stevenson "as well as members of his family" have committed "fraud and corruption".Worldview said it opted to publish the letter in the wake of "public allegations", which claimed Stevenson, who is in charge of the company's Ain Tsila gas field development in Algeria, may have benefited from "a scheme designed to 'defraud the company'" by hiring contractors through a company called Petroplan using "overstated invoices".As a result of the allegations, Worldview said Stevenson is no longer thought to be the project director."If correct, these public allegations suggest that shareholder value may have been compromised by the overpayment for services and/or funds being fraudulently diverted away from Petroceltic and thus its shareholders," it said.The letter also contained a number of questions addressed to Petroceltic, which are aimed at clarifying the situation, as well as shedding light on what the company has done to investigate the allegation and Stevenson's role in the matter."As the largest shareholder in Petroceltic, and following our sustained and constant efforts over the last 14 months to proactively engage with the board to improve Petroceltic's governance, we are disappointed to again raise issues that, if substantiated, further evidence a culture of inappropriate and failed governance," it said.The company has called an extraordinary general meeting for 7 September, when shareholders will vote on a separate issue raised by Worldview over Petroceltic's disposal policy.Worldview has offered Petroceltic a resolution, which would see the oil and gas explorer seeking approval from shareholders for any asset disposals which represents 25% or more of the company's revenues and profits.Petroceltic shares were down 6.48% to 50.50p at 0927 BST on Thursday.