In a pay-TV broadcast, an authorised user may decrypt the content and re-broadcast it. In Crypto 99, Fiat and Tassa proposed dynamic tracing schemes that can trace a group of colluders who attempt to re-broadcast the content. We show an attack on their scheme and propose a new tracing scheme, called sequential tracing scheme, that can capture all colluders and minimises real-time computation. We show application of this scheme to fingerprinting digital content.