Federal law enforcement agencies are currently investigating the breach which occured late last year. So far 750 people have been the victims of identity theft as a result of the incident.

ChoicePoint says the fraudsters posed as customers with a lawful purpose for accessing information about individuals. The gang may have accessed customers' names, addresses, social security numbers and credit reports.

The firm has sent letters 35,000 residents in California warning that their information may have been accessed. California is the only state where companies are required to notify people when personal data is exposed. ChoicePoint says it will also be sending letter to 110,000 consumers across the US whose information also may have been accessed.

In a statement, ChoicePoint says the incident was not a breach of its network but it is updating processes and procedures to ensure the integrity of its systems.

Spun off from Equifax in 1997, ChoicePoint maintains approximately 19 billion records on individuals culled from multiple information sources.