The parties can bring relevant certificates to the Public Security Bureau to register and report the case. If you don't know the identity of the other party after receiving the SMS for the first time, you can file a case first, and you can report the case directly after receiving the SMS for the second time.
Legal basis: Article 42 of the Law of People's Republic of China (PRC) on Public Security Administration Punishment commits one of the following acts, and shall be detained for not more than five days or fined not more than five hundred yuan; If the circumstances are serious, they shall be detained for more than five days and less than ten days, and may be fined up to five hundred yuan:
(1) writing threatening letters or threatening the personal safety of others by other means;
(2) publicly insulting others or fabricating facts to slander others;
(3) fabricating facts, falsely accusing and framing others, and attempting to subject others to criminal investigation or public security administration punishment;
(4) Threatening, insulting, beating or retaliating against witnesses and their close relatives;
(five) sending obscene, insulting, threatening or other information for many times, interfering with the normal life of others;
(six) voyeurism, sneak shots, eavesdropping, spreading the privacy of others. Article 246 of the Criminal Law of People's Republic of China (PRC) publicly insults others or fabricates facts to slander others by violence or other means, if the circumstances are serious, he shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention, public surveillance or deprivation of political rights.
The crimes mentioned in the preceding paragraph shall be dealt with only if they are told, except those that seriously endanger social order and national interests.
If the victim informs the people's court of the acts specified in the first paragraph through the information network, but it is really difficult to provide evidence, the people's court may request the public security organ to provide assistance. Interpretation of several issues concerning the application of law in handling criminal cases such as defamation by using information network Article 3. Using information network to slander others, under any of the following circumstances, shall be deemed as "seriously endangering social order and national interests" as stipulated in the second paragraph of Article 246th of the Criminal Law:
(1) Causing mass incidents;
(2) Causing public disorder;
(3) Causing ethnic and religious conflicts;
(four) slander many people, causing adverse social impact;
(5) Damaging the national image and seriously endangering the national interests;
(6) Causing adverse international influence;
(seven) other circumstances that seriously endanger social order and national interests.