She was on season one.

Cassandra Waldon, the very first "Big Brother" contestant to enter the house on the U.S. version, has died.
Cassandra passed away on September 25 ... apparently from injuries related to a car accident in Rome. A source at the United Nations -- where Cassandra worked -- tells TMZ ... she was struck by a car about 2 months ago, and suffered a head injury. We're told she never regained consciousness before her death.