it affects an undefined number of people that were under investigation by the office between 2002 and 2014 - this could be subjects, witnesses and complainants, and is not limited to DHS employees.
[..]
anyone potentially affected was being offered 18 months of free credit monitoring and identity protection services.
So free credit monitoring for everyone, right? If they can't tell who is affected, anyone is potentially affected.
Biting the hand that feeds IT
