Sam Cannon handed over his passport details to the detective, believing that she had traced the father he had never known.
However, she was actually working for a woman with whom Mr Cannon was involved in a legal battle.
When his 25-year-old criminal record from his youth turned up in the civil action, he believed that his passport details had been used to get it.
Mr Cannon, who won the court battle, complained to the police about the accessing of his details but was surprised to be told by them and the Law Officers that no law had been broken.
The owner of the private detective agency, David Watkins, defended his actions, saying that he was involved in the pursuit of truth and that morality was a ‘side issue’.
However, after reading about the case in the JEP, Data Protection Commissioner Emma Martins has decided to investigate.
‘Any processing of personal data is going to be a data protection issue,’ she said.