What Was The Role of David Herold

[RJNorton]

Thanks, Betty!

Here is an example of what I have read in so many books. This is from James Swanson's Manhunt:

"David Herold would accompany Powell, direct him to Seward's home, and then guide the assassin, unfamiliar with the capital's streets, out of the city." (p. 29)

As Powell had already scouted the Seward home previously, I just don't understand why so many authors "assume" he needed to be guided to the home on the night of the 14th.