(6)Where any person subject to this Act is being tried on a charge of desertion or of absence without leave, and such person has surrendered himself into the custody of, or has been apprehended by, a police officer not below the rank of an officer in charge of a police station, a certificate purporting to be signed by such police officer and stating the fact, date and place of such surrender or apprehension and the manner in which he was dressed shall be evidence of the matters so stated.
