This disclosure describes methods and systems for a biometric identity management system capable of being deployed incrementally one organization at a time, and also reversibly, such that any organization can unsubscribe at any time. A biometric processing engine can perform biometric matching between records from a first database and a second database, whereby the databases have been established independently of each other. Each record comprises a biometric record and a corresponding identifier unique across databases. If a biometric record of a first record and a biometric record of a second record are from a same individual, the first record comprising a first unique identifier and the second record comprising a second unique identifier are linked. Using the first or second unique identifiers, access to information about the individual linked to both the first record in the first database and the second record in the second database is provided.