On 22 February 2012, Sinclaire was arrested along with three other people; two women aged 55 and 39, as well as a 19-year-old man on suspicion of conspiracy to defraud the European Parliament following an inquiry into an allegation made in 2010, concerning allowances and expenses. Sinclaire denied all the charges, cooperated with the police, and while the investigation was in process would only state that it was tied to a disgruntled employee who was themselves the subject of a similar investigation. On 23 July 2014, she was charged with money laundering, contrary to Sections 327 or 329 of the Proceeds of Crime Act 2002, and misconduct in public office, contrary to Common Law, relating to European Parliament travel expenses, in a period between October 2009 and July 2010.