Little is known about men who sexually abuse multiple children and evade detection for long periods. This group is responsible for inflicting significant harm due to the severity, and longevity of their offending. The aim of the study was to identify men who perpetrate persistent sexual offences against children and differentiate them by those with long detection lags (LDLs) (n = 35) and short detection lags (SDLs) (n = 35) using police databases and case files. The men were compared on demographic characteristics, lifestyle factors, victimisation, psychopathic traits, antisocial orientation, atypical sexual interest, and descriptive sexual offence variables. The LDL participants had more psychopathic traits, more pre-pubescent child victims, more often be in professional employment and have less antisocial and criminogenic indicators than the comparative SDL group. These findings have significant practical implications for reduced victimisation through early identification, forensic risk assessment, treatment and earlier prevention strategies for CSA. Practice impact statement: The current findings have important and practical implications within forensic risk assessment, especially Structured Professional Judgement (SPJ) when assessing specific groups of offenders. In addition, research informed SPJ can better prioritise policing investigative resources, both retrospectively (e.g. identifying victims) and prospectively (e.g. reducing detection lags and victimisation) while defensively informing the criminal justice system of the most appropriate supervision intensity and intervention modalities for men with clinical and forensic indicators of potential high victimisation and longer detection lags.