This article explores the dynamics of cases involving family and acquaintance sexual offenders who used the Internet to commit sex crimes against minors. Although the stereotype of Internet crimes involves unknown adults meeting juvenile victims online, Internet use can also play a role in sexual crimes against minors by family members and acquaintances. Data were collected from a national sample of law enforcement agencies about arrests for Internet-related sex crimes against minors. Family and acquaintance offenders were nearly as numerous as offenders who used the Internet to meet victims online. They used the Internet in various ways to further their crimes including as a tool to seduce or groom, store or disseminate sexual images of victims, arrange meetings and communicate, reward victims, or advertise or sell victims. Prevention messages and investigation approaches should be revised to incorporate awareness of such cases and their dynamics.