In some aspects, a computing system can generate entity links between a primary entity object identifying a primary entity for multiple accounts and secondary entity objects identifying secondary entities from the accounts. The computing system can determine a rate at which secondary users change on the accounts. The computing system can update, based on the determined rate, the primary entity object to include a fraud-facilitation flag. The computing system can also service a query from a client system regarding a presence of a fraud warning for a target consumer associated with a consumer system that accesses a service provided with the client system. For instance, the computing system can generate a fraud warning based on the target consumer being identified in a secondary entity object associated with the primary entity object having the fraud-facilitation flag. The computing system can transmit the fraud warning to the client system.