Without the requested information, I can only provide you with the following general response, which will hopefully still answer your query.
You cannot obtain a person’s criminal record unfortunately as that information will be protected under strict data protection laws, such as the GDPR. Only the person themselves, or parties with legitimate legal interests can request details of that person’s criminal record. These would most commonly include prospective employers who require a criminal records check to determine that person’s suitability for the employment they have offered them. Even then, the person’s consent will be required for the check to be carried out.
Therefore, you will have to get the person’s consent to be able to access their criminal record and I doubt you would want to do that as it will alert them that you are suspicious.
The alternative is to engage a private investigator who may be able to gain access to some information linked to his criminal past but it would be best to approach them first to see what their services can offer and if this is a feasible option.
Hopefully, I have answered your query in a way that is simple and easy to understand. If anything remains unclear, I will be more than happy to clarify it for you. In the meantime, thank you once again for using our services.