Patisserie Valerie owner Patisserie Holdings said on Friday that Chris Marsh, its suspended finance director, was arrested by the police on Thursday night and had been released on bail.
Patisserie warned on Thursday that it is in danger of collapse if it cannot urgently raise capital after discovering a potential accounting fraud.
Friday's statement comes after the company disclosed an accounting fraud earlier this week that led to the company suspending Marsh.
Patisserie Holdings said on Thursday that an investigation had found a "material shortfall" between the reported accounts of the London-listed company and its true financial health.
Marsh did not immediately return a request for comment from Reuters on social media site LinkedIn.
Marsh, who joined the company in 2006, was an integral part of the company's growth. Patisserie had just eight stores in 2008 and now operates more than 200 in Britain.
Shares of the company remain suspended from trading.