We explored heterogeneity (subgroups) amongst victims and suspects of modern slavery offences using a cross-sectional extract of police data from a large metropolitan area in the UK with details of 540 victims and 380 suspects (reported to the police between April 2015 and June 2018). Latent class analysis was used to identify subgroups of victims and suspects based on the manifest demographic (age, sex, and place of birth) and exploitation type variables. Amongst suspects, classes distinguished between ‘Male sex traffickers’ (82%) and ‘Labour and domestic traffickers’ (18%). Amongst victims, four classes were identified as: ‘Sexually and domestically exploited women’ (30%) and ‘Sexually exploited girls’ (35%), ‘Men exploited in licit and illicit markets’ (26%), and ‘Criminally exploited boys’ (9%). These findings reveal trafficking as structured by gender, generation, and migration, but caution against defining the problem as one of exclusively male offenders exploiting women and children victims, even while this is commonplace.