Upon the expiration of the period of parole the parolee shall be discharged. At any time during the period of parole the parolee may be arrested for the violation of any condition of his parole, and after a hearing by the board his parole shall be subject to revocation. Any parole officer, police officer or other law enforcement officer may arrest a parolee with or without a warrant for the violation of any condition of his parole. In case of an arrest without a warrant, the arresting officer shall have a written statement by a parole officer setting forth that parolee has, in the judgment of the parole officer, violated the conditions of his parole. Such statement shall be sufficient warrant for the detention of said parolee until he can be brought before a parole officer. Such parole officer, after advising said parolee in writing of the charged violation and hearing any evidence or explanation offered by parolee in his defense shall, if not satisfied from the evidence or explanation of the parolee, forthwith submit to the board a written report of such violation. Upon receipt of such report the board shall set a hearing date to determine if such parole shall be revoked. The parolee at such hearing may be represented by counsel and present evidence in his defense, In the event such parole is revoked, the board shall prepare a written opinion stating the evidence relied upon and the reason for such revocation. The parolee, upon such revocation, shall serve his sentence as though no parole had been granted him, notwithstanding his sentence would have ended but for the suspension thereof by parole.