Upon the receipt of an application for a certificate, the chief of police or sheriff shall issue a certificate or deny a certificate and furnish the applicant the specific reasons for the denial in writing. The chief of police or sheriff shall be permitted up to three days in which to conduct an investigation to determine whether the applicant is prohibited by law from purchasing or possessing a handgun. If the certificate or denial is mailed to the applicant, it shall be mailed to the applicant's address by first-class mail within the three-day period. If it is determined that the purchase or possession of a handgun by the applicant would be in violation of applicable federal, state, or local law, the chief of police or sheriff shall deny the certificate. In computing the three-day period, the day of receipt of the application shall not be included and the last day of the three-day period shall be included. The three-day period shall expire at 11:59 p.m. of the third day unless it is a Saturday, Sunday, or legal holiday in which event the period shall run until 11:59 p.m. of the next day which is not a Saturday, Sunday, or legal holiday. No later than the end of the three-day period the chief of police or sheriff shall issue or deny such certificate and, if the certificate is denied, furnish the applicant the specific reasons for denial in writing. No civil liability shall arise to any law enforcement agency if such law enforcement agency complies with sections 69-2401, 69-2403 to 69-2408, and 69-2409.01.