How to Find Offshore Bank Accounts
Determine the name of the account holder. It is not uncommon for someone to use the name of in-laws, a wife's maiden name, or other relatives to set up an account.
If conducting the search on your own, start by trying to find the signer of the account. A signer will have their name on the account, but can use the social security number of other people on the account instead of their own. The signer still maintains control over funds including the ability to issue checks and close out the account.
Get a copy of the person's tax return. While offshore banks may not be required to include this information, it is considered perjury to not include all information regarding limited partnerships, bank accounts and other income generating sources to the IRS. The IRS has recently started to go after Swiss banks in an effort to capture back taxes. See Resources for an article.
Conduct a public records search. Many of these services charge a small fee. See Resources for a link to the Public Records website.
Hire an attorney to issue a subpoena for records. Many attorneys use asset search firms before they will accept your case, so this might be a good first step if you can afford the initial retainer.
Hire a detective or asset search firm. Go to the World Association of Detectives to locate a firm. Use the "Membership Directory" for a list of contacts by location. See Resources for a link.