Bahrain’s Gulf Finance House has become entangled in a dispute with a former executive at its Dubai-based private equity unit who the company alleges falsified invoices to siphon almost $5 million into bank accounts controlled by him. David Haigh, who was the deputy chief executive of GFH Capital until resigning this March, was arrested shortly after he arrived in Dubai about a month ago and has been in detention since. Legal authorities in Dubai are weighing criminal charges, according to an emailed statement from GFH, while the company has also filed a civil suit against him in the Dubai International Financial Centre. Mr. Haigh denied the GFH allegations.