We assessed the prevalence of bullying and cyberbullying in 12-16-year-olds and the association with student self-reports after a police informative talk. We used a survey to assess the impact of the intervention: 1458 high school students received a police informative talk during the 2018-2019 school year and completed the self-administered EBIP-Q and ECI-Q questionnaires. Perceptions of conduct and bystanders' attitudes were assessed. Correspondence indexes were calculated using Cohen's kappa and gender differences studied using logistic regression. 81.34% (95% CI: 79.33-83.34) of students were involved in bullying and 54.75% (95% CI: 52.19-56.76) in cyberbullying. Almost 90% of participants did not perceive their real bullying correctly. Girls were more frequently victims of bullying and cyberbullying (OR=1.67 and OR=1.22, p=.004), but more frequently self-reported being bullies or victim/bully (OR=0.57 and 0.39, p<.05). Male bystanders reported 7.33% (p<.001) more feelings of inadequacy than girls when witnessing bullying. Poor self-reporting reflects poor understanding of bullying and cyber-bullying. Police information sessions might produce the opposite reactions in adolescents, as they reduce bullying to visible, harmful violence. Educators should focus on adolescent relationships rather than violence prevention. A friendly, male-targeted approach is needed.