When hiring a private investigator, do your research, as all private investigators are not created equal. It is important to hire a former police officer and/or investigator with experience working for state criminal investigations, and federal officers such as the FBI.
The market is full of low-level investigators, which are known to take your money, and run! Many of these low-level detectives will make bold claims on their website stating that they have law enforcement and intelligence experience without providing evidence of certificates of recommendations, or photos of their service on the force. When they lie about their experience, they will cause a major disservice to your case.
Do your research and hire the best private investigator who will solve your problem!