If she was suspected of fraud then inform, arrest her and make plans for this suspicion to be tested by trial, no? As I understand it she was "detained" rather

If she was suspected of fraud then inform, arrest her and make plans for this suspicion to be tested by trial, no? As I understand it she was "detained" rather than arrested, told outright that she had not committed a criminal offence, and was offered no further insight into her situation or when/where/how she would be released.