"Agnes Carver," she said.
Hart's pen stopped moving. "Who is Agnes Carver?"
"She was Mercer's bookkeeper until April of this year," Margaret said slowly, thinking it through as she said it. "She left suddenly. I assumed at the time that Mercer had let her go when he started expecting trouble from me, that he'd wanted to reduce anyone with access to his internal records." She looked at Nathan. "But what if she left on her own? What if she saw something she wasn't supposed to see?"
"Do you know where she went?"
"I don't. But her sister lives in Benton Springs." She stood up. "That's twenty miles north. I know the sister."
Nathan was already pushing back from the table.
"Sit down," Margaret said. "You can't ride twenty miles tonight."
"I can leave at first light."
"We both leave at first light," she said. "I know the sister better than you do."
Nathan sat back down. Thomas looked between them with an expression Margaret didn't examine—the expression of a young man observing something and filing it quietly.
"If Agnes Carver saw Mercer alter records and was dismissed or pressured to leave because of it," Hart said carefully, "and if she can be located and is willing to testify, that changes the case from strong to decisive."