Richard Sarles may be in charge of WMATA for the interim, but the transit agency still needs to find a permanent replacement for John Catoe. On Thursday, Metro’s board gave approval to hiring executive search firm Heidrick & Struggles to help them with the task. It’s going to cost the cash-strapped agency $150,000 to hire the firm for a roughly six-month search. Heidrick & Struggles has previously conducted searches for chief executives to lead the American Red Cross and Howard University. Metro says the firm will look both nationally and internationally, within the transit industry and beyond for candidates for a new general manager.