(1) An inmate may not be granted a release on parole by the board until it has made, or caused to be made, an investigation concerning:

(a)The inmate's previous social history and criminal record;

(b)The inmate's education, conduct and associations;

(c)The inmate's occupation or prospects for employment;

(d)The inmate's treatment record in prison;

(e)Facts and circumstances of the crime for which sentenced;

(f)Information received from the community where the crime was committed;

(g)Summary and recommendation of a parole officer concerning the offender release plan; and

(h)Any reports of physical or mental examinations which have been made of the offender.