You can report it without direct evidence. As long as you don't fabricate facts and evidence, even if the facts of the accusation and the report are different, or even false accusation, it will be strictly distinguished from false accusation.

Criminal procedure law

Article 109 Reports, complaints and reports may be made in written form or orally. The staff who accept the oral report, complaint or report shall make a written record, which shall be signed or sealed by the informant, complainant and informant after being correctly read out.

The staff who accept the complaint and report shall explain the legal responsibility of false accusation and frame-up to the complainant and informant. However, as long as it is not fabricating facts and evidence, even if the facts of the accusation and report are different, or even false accusation, it should be strictly distinguished from false accusation.

Public security organs, people's procuratorates or people's courts shall ensure the safety of informants, complainants, informants and their close relatives. Informants, complainants and informants who are unwilling to disclose their names and report, accuse and report their acts shall keep them confidential.

Article 110 A people's court, a people's procuratorate or a public security organ shall, within the scope of their jurisdiction, promptly examine the materials of reporting, accusing, reporting and surrendering themselves, and if they think that there are criminal facts that need to be investigated for criminal responsibility, they shall file a case; If it is considered that there are no criminal facts, or the criminal facts are obviously minor, and it is not necessary to pursue criminal responsibility, the case shall not be filed, and the complainant shall be informed of the reasons for not filing the case. If the complainant refuses to accept it, he may apply for reconsideration.