Peter A. Kryzek was named executive director of the Montgomery County Board of Investment Trustees and will oversee the $1.8 billion Montgomery County Employees' Retirement System, Rockville, Md. He replaces Patrick Bell, who left in September. Linda Herman, who has been acting executive director, will resume her role as senior investment officer at the system. Mr. Kryzek was partner overseeing marketing and client services in the Hartford, Conn., office of Rice Hall, James & Associates. No information was available on a replacement.