The evidence that sealed Mrs. Surratt's fate

[BettyO]

I agree, Roger.

According to one resource, Powell once mentioned something in regards to the kidnap plot in the parlor where they were all seated. John Surratt immediately collared Powell and took him out into the hallway and told him to "Never mention the kidnapping plot in front of my mother again. She doesn't know and doesn't need to know!"

Whether this is true or not I don't know -- but I think that Mary DID know about the plot - more than was revealed. Powell didn't know how much she knew apparently.