For the purpose of enabling the Attorney General to perform the duties imposed by Section 13 of Article V of the Constitution the Attorney General may appoint and fix the compensation of special agents and investigators not exceeding 10 in number as deemed necessary. The Attorney General shall not be required to divulge their identities. They may be employed either on a monthly basis or by the day. Each special agent or investigator shall take an oath of office, the record of which shall be kept in the private files of the Attorney General.