source: The Friday Caller (Plainfield, Indiana) - issue of Thursday, December 9, 1954 - page 1, columns 2-4:
According to a newspaper article, in November 1954 voters approved a referendum to abolish the town's system of town marshals and instead create a police department. This was in response to a 1951 state law which allowed any town with a population of more than 3,000 to allow its residents to vote to establish a "board of metropolitan police commissioners" and abolish the office of town marshal. This system would go into effect in January 1955.
Laurence Bradley, Dr. R.H. Marlowe and Ed Cox were appointed by the town's trustees to be the first police commissioners.