The Metropolitan Police put no allegations to Rebekah Brooks during nine hours of interviews, her solicitor said today as he described the decision to arrest her as causing "enormous reputational damage".
Stephen Parkinson, of Kingsley Napley, said the former News International chief executive was also not shown any documents connecting her to any crime during questioning yesterday.
It was earlier confirmed the Ms Brooks will definitely appear before a committee of MPs tomorrow to answer questions about the phone-hacking affair despite her arrest.
Mr Parkinson said: "The position of Rebekah Brooks can be simply stated: She is not guilty of any criminal offence.
"The position of the Metropolitan Police is less easy to understand. Despite arresting her yesterday and conducting an interview process lasting nine hours, they put no allegations to her, and showed her no documents connecting her with any crime.
"They will in due course have to give an account of their actions, and in particular their decision to arrest her, with the enormous reputational damage that this has involved.
"In the meantime, Mrs Brooks has an appointment with the Culture, Media and Sport Select Committee tomorrow. She remains willing to attend and to answer questions.
"It is a matter for Parliament to decide what issues to put to her and whether her appointment should take place at a later date."
The 43-year-old was arrested by Scotland Yard and bailed after being questioned for several hours yesterday.
The development led to speculation that she would not appear before the committee tomorrow, when she faces tough questions from MPs, alongside Rupert Murdoch and his son James.
The Met declined to respond.