(a) The sheriff may depute a proper person to serve a writ at the risk of the plaintiff in such writ by indorsing thereon a special deputation, and, when he or she deems it necessary, may depute some person to serve a warrant in a criminal cause or any other precept by indorsing a special deputation on such writ or precept.

(b) Such special deputy shall make oath to his or her service and return and that he or she did not make or alter the writ, warrant, or precept by him or her served. He or she shall cause to be indorsed thereon a certificate of such oath. Service so made shall be as valid as if made by the sheriff.