It was Spencer. She went by herself, luckily.
"What do you want, Voight? Is this one of your moves to get Lindsay back? That's not happening" she said. Couldn't Erin just leave the FBI by herself? What had happened 4 years ago that I didn't know about? Was a deal made between them?
"I've got photos of you exchanging information for money, plus numerous calls tied to russians phone numbers. I've done my homework. You are committing treason. I think the FBI will like to know this, don't you think?" Hank replied.
She was speechless, someone had caught her."It's.. It's not what it looks like" she answered.
"Then explain, because I'm halfway a call to your bosses".
Then Spencer started explaining that what she received in exchange were photos, not money. Her little sister had been kidnapped by them and she had been giving them information to keep her alive, to keep her safe. "Why didn't you take it to the police? Why didn't you try to find her?" he asked. "They said they had spies everywhere. If they found out I was looking for her, they would kill her... You gotta understand. I didn't have a choice" Spencer said.