The CIA does not involve itself in banking disputes. They might investigate and collect evidence, but usually it is the FBI working with the treasury.
As far as seizure of $$$ in foreign countries, there has to be an agreement between countries, and each will spell out what and how. Not all agreements will be the same.
Once the US courts declare seizure, the treasury departments works with the treasury of other countries as well as banks. If they don't want to play ball with us, then the US can put restrictions on business with those banks, or governments.
The U.N. has some type of banking laws as well which all member nations must abide by.
The President can also sign a freeze or forfeiture decree on individuals, countries, or corporations as has been done for Iran, Libya, North Korea and other countries.