ABC7 News has confirmed FBI agents are inside the Charlotte home of Petraeus's mistress Paula Broadwell Monday night.
They've been seen at the home with cameras and boxes.
Sources say Petraeus was shocked when he found out Broadwell had been sending threatening emails to another woman.
Broadwell began sending the emails to Jill Kelley in May.
They allegedly warned Kelley to stay away from Petraeus.
He has told associates his relationship with Kelley was platonic.
On Broadwell's computer the FBI found explicit emails she had exchanged with Petreaus, as well as possibly classified military documents.
Petraeus says those documents didn't come from him.