Section 6. There shall be within the division of investigation and intelligence two bureaus, which shall be designated as the bureau of investigative services/eastern region and the bureau of investigative services/western region. The head of each such bureau shall be designated by the colonel and shall hold such rank or temporary rank as the colonel may determine. The colonel may from time to time assign to each such bureau such uniformed members and other employees of the department as he may deem necessary to carry out its duties.